diff --git a/src/lib/inbox-three/line-rows.test.ts b/src/lib/inbox-three/line-rows.test.ts
new file mode 100644
index 0000000..5591c23
--- /dev/null
+++ b/src/lib/inbox-three/line-rows.test.ts
@@ -0,0 +1,146 @@
+import { describe, expect, it } from "vitest";
+import { buildPreview, type PreviewContext } from "@/lib/dn-pipeline/ai-preview";
+import { buildLineRows, editToConfirmation, UNIT_SUGGESTIONS, type LineEdit } from "./line-rows";
+
+/**
+ * The fencing slip 0007075669 against MEGCPO9448.
+ *
+ * The slip prints two rolls of mesh at R1 298 (VAT inclusive). The order
+ * carries the same goods as 2 "m" at R1 124.35 — the PO's unit label is
+ * wrong, which is exactly the question the office has to answer.
+ */
+const MESH_ITEM = "meshitem1234567";
+const KERB_ITEM = "kerbitem12345678";
+
+const context = (): PreviewContext => ({
+  note: { id: "noteabcdefghijk", batch: "batchabcdefghij", pages: [1], doc_number: "0007075669", items: [] },
+  pages: [],
+  supplier: { id: "supplierabcdefg", name: "Vula" },
+  po: { id: "poabcdefghijklm", purchase_order_number: "MEGCPO9448", total_value: 2248.7 },
+  poItems: [
+    { id: MESH_ITEM, description: "MESH DIAMOND 600 x 2.5 ROLL", unit: "m", qty: 2, rate: 1124.35, disc_percent: 0, vat_percent: 15 },
+    { id: KERB_ITEM, description: "KERB 150", unit: "ea", qty: 10, rate: 95, disc_percent: 0, vat_percent: 15 },
+  ],
+  lines: [
+    { sourceLineId: "mesh", description: "MESH DIAMOND … ROLL", qty: 2, unit: "roll", unit_price: 1298, line_amount: 2596, product_code: null },
+    { sourceLineId: "kerb-a", description: "KERB 150", qty: 4, unit: "ea", unit_price: 95, line_amount: 380, product_code: null },
+    { sourceLineId: "kerb-b", description: "KERB 150", qty: 4, unit: "ea", unit_price: 95, line_amount: 380, product_code: null },
+    { sourceLineId: "kerb-c", description: "KERB 150", qty: 4, unit: "ea", unit_price: 95, line_amount: 380, product_code: null },
+  ],
+  priorDeliveries: [],
+  priorItems: [],
+});
+
+const preview = (c: PreviewContext) => buildPreview(c, { allocations: [
+  { sourceLineIds: ["mesh"], purchaseOrderItemId: MESH_ITEM, quantityBasis: "direct", factor: 1, amountBasis: "po_rate", sourceAmountBasis: "unknown", ruleKeys: [], explanation: "Mesh diamond roll", reviewQuestion: null },
+  { sourceLineIds: ["kerb-a"], purchaseOrderItemId: KERB_ITEM, quantityBasis: "direct", factor: 1, amountBasis: "po_rate", sourceAmountBasis: "unknown", ruleKeys: [], explanation: "Kerb", reviewQuestion: null },
+  { sourceLineIds: ["kerb-b", "kerb-c"], purchaseOrderItemId: KERB_ITEM, quantityBasis: "kit", factor: 1, amountBasis: "po_rate", sourceAmountBasis: "unknown", ruleKeys: [], explanation: "Kerb pair", reviewQuestion: null },
+] });
+
+const edit = (over: Partial<LineEdit> = {}): LineEdit => ({
+  lines: [1],
+  poItemId: MESH_ITEM,
+  slipQty: 2,
+  slipUnit: "roll",
+  factor: 1,
+  price: null,
+  usePoRate: true,
+  reason: "",
+  ...over,
+});
+
+describe("buildLineRows", () => {
+  it("shows the slip's roll against the order's metre", () => {
+    const c = context();
+    const row = buildLineRows(c, preview(c))[0];
+    expect(row.numbers).toEqual([1]);
+    expect(row.slipText).toBe("MESH DIAMOND … ROLL");
+    expect(row.slipQty).toBe(2);
+    expect(row.slipUnit).toBe("roll");
+    expect(row.poItemId).toBe(MESH_ITEM);
+    expect(row.poUnit).toBe("m");
+    expect(row.poRate).toBe(1124.35);
+    expect(row.ordered).toBe(2);
+    expect(row.flags).toContain("unit_differs");
+  });
+
+  it("values the line at the order rate and says what is left on the order", () => {
+    const c = context();
+    const row = buildLineRows(c, preview(c))[0];
+    expect(row.factor).toBe(1);
+    expect(row.poQty).toBe(2);
+    expect(row.value).toBe(2248.7);
+    expect(row.leftOnPo).toBe(0);
+  });
+
+  it("asks how many order units one roll is when nobody said", () => {
+    const c = context();
+    const p = preview(c);
+    p.allocations[0].factor = null;
+    const row = buildLineRows(c, p)[0];
+    expect(row.flags).toContain("factor_missing");
+    expect(row.problem).toBe("Enter how many m one roll is");
+    expect(row.value).toBeNull();
+  });
+
+  it.each([0, -1, 20000])("refuses a factor of %s", (factor) => {
+    const c = context();
+    const p = preview(c);
+    p.allocations[0].factor = factor;
+    const row = buildLineRows(c, p)[0];
+    expect(row.flags).toContain("factor_missing");
+    expect(row.value).toBeNull();
+  });
+
+  it("numbers a combined row by the slip's own line numbers", () => {
+    const c = context();
+    const rows = buildLineRows(c, preview(c));
+    const combined = rows.find((row) => row.numbers.length > 1);
+    expect(combined?.numbers).toEqual([3, 4]);
+  });
+
+  it("offers the unit suggestions the clerk can pick", () => {
+    expect(UNIT_SUGGESTIONS).toContain("roll");
+    expect(UNIT_SUGGESTIONS).toContain("m");
+  });
+});
+
+describe("editToConfirmation", () => {
+  it("turns two rolls into sixty metres with the factor on the line", () => {
+    const c = context();
+    const row = buildLineRows(c, preview(c))[0];
+    const confirmation = editToConfirmation(row, edit({ factor: 30 }), "m");
+    expect(confirmation).toMatchObject({ quantity: 60, unit: "m", usePoRate: true });
+    expect(confirmation.reason).toBe("2 roll × 30 = 60 m");
+  });
+
+  it("uses the edited price instead of the order rate", () => {
+    const c = context();
+    const row = buildLineRows(c, preview(c))[0];
+    const confirmation = editToConfirmation(row, edit({ price: 1298, usePoRate: false }), "m");
+    expect(confirmation).toMatchObject({ netAmount: 2596 });
+    expect(confirmation.usePoRate).toBeUndefined();
+    expect(confirmation.reason).toContain("Price R1298");
+  });
+
+  it("overrides a wrong order unit label when the factor is one", () => {
+    const c = context();
+    const row = buildLineRows(c, preview(c))[0];
+    const confirmation = editToConfirmation(row, edit({ factor: 1 }), "m");
+    expect(confirmation).toMatchObject({ quantity: 2, unit: "roll", unitOverride: true });
+    expect(confirmation.reason?.trim()).not.toBe("");
+  });
+
+  it.each([null, 0, -1, 20000])("refuses to confirm with a factor of %s", (factor) => {
+    const c = context();
+    const row = buildLineRows(c, preview(c))[0];
+    expect(() => editToConfirmation(row, edit({ factor }), "m")).toThrow(/Enter how many m one roll is/);
+  });
+
+  it("always gives a reason", () => {
+    const c = context();
+    const row = buildLineRows(c, preview(c))[0];
+    expect(editToConfirmation(row, edit({ factor: 1 }), "m").reason?.trim()).not.toBe("");
+    expect(editToConfirmation(row, edit({ factor: 1, reason: "the order unit is wrong" }), "m").reason).toBe("the order unit is wrong");
+  });
+});
diff --git a/src/lib/inbox-three/line-rows.ts b/src/lib/inbox-three/line-rows.ts
new file mode 100644
index 0000000..14fa922
--- /dev/null
+++ b/src/lib/inbox-three/line-rows.ts
@@ -0,0 +1,187 @@
+/**
+ * The Inbox 3 line rows.
+ *
+ * One row per allocation, in the order the slip printed its lines: what the
+ * slip says, what the order says, what the row books, and what is still in
+ * the way. The office reads this instead of a matched-to-against table,
+ * because the question on a slip is rarely "which line" — it is "how many
+ * of the order's unit is one of mine".
+ *
+ * Pure. No I/O and no posting: a row says what is true, and a person
+ * confirms.
+ */
+import { finiteNumber, type PreviewAllocation, type PreviewContext, type PreviewLine, type ProcessingPreview } from "@/lib/dn-pipeline/ai-preview";
+import type { LineConfirmation } from "@/lib/dn-pipeline/line-booking";
+import { sameReceivingUnit } from "@/lib/dn-pipeline/receiving-defaults";
+import { guardAgrees, lineReady, priceFlagged } from "@/lib/inbox-three/readiness";
+
+export interface LineEdit {
+  /** 0-based indexes into the note's saved lines. */
+  lines: number[];
+  poItemId: string | null;
+  slipQty: number;
+  slipUnit: string;
+  /** How many order units one slip unit is. */
+  factor: number | null;
+  /** The edited unit price, or null to keep the order rate. */
+  price: number | null;
+  usePoRate: boolean;
+  reason: string;
+}
+
+export interface LineRow {
+  /** 1-based slip line numbers this row covers; a combined row reads "3+4". */
+  numbers: number[];
+  allocationIndex: number;
+  slipText: string; slipQty: number | null; slipUnit: string | null; slipPrice: number | null; slipAmount: number | null;
+  poItemId: string | null; poUnit: string | null; poRate: number | null; ordered: number | null; priorReceived: number;
+  qty: number | null; unit: string | null; factor: number | null; poQty: number | null;
+  price: number | null; value: number | null; leftOnPo: number | null;
+  flags: Array<"unit_differs" | "factor_missing" | "price_differs" | "over_po" | "guard_conflict" | "not_on_po">;
+  ready: boolean; posted: boolean; problem: string | null;
+}
+
+export const UNIT_SUGGESTIONS = ["each", "roll", "m", "m²", "m³", "kg", "5kg bag", "ton", "length", "box", "pack"] as const;
+
+const round2 = (n: number) => Math.round((n + Number.EPSILON) * 100) / 100;
+/** A factor has to be a real conversion: above zero and no bigger than a roll of 10000. */
+const usableFactor = (value: unknown): value is number =>
+  typeof value === "number" && Number.isFinite(value) && value > 0 && value <= 10000;
+
+/** What this note has already booked against an order line. */
+function bookedForItem(context: PreviewContext, poItemId: string | null): number {
+  if (!poItemId) return 0;
+  const state = context.note.line_posting as { bookings?: { poItemId?: string; qty?: number }[] } | undefined;
+  return (state?.bookings ?? []).filter((booking) => booking.poItemId === poItemId).reduce((sum, booking) => sum + (finiteNumber(booking.qty) ?? 0), 0);
+}
+
+/** What other notes have already delivered against an order line. */
+function priorReceivedForItem(context: PreviewContext, poItemId: string | null): number {
+  if (!poItemId) return 0;
+  return context.priorItems.filter((row) => row.purchase_order_item === poItemId).reduce((sum, row) => sum + (finiteNumber(row.qty_received) ?? 0), 0);
+}
+
+function buildRow(
+  context: PreviewContext,
+  preview: ProcessingPreview,
+  allocation: PreviewAllocation,
+  allocationIndex: number,
+  lineNumbers: Map<string, number>,
+): LineRow {
+  const source = allocation.sourceLineIds
+    .map((id) => context.lines.find((line) => line.sourceLineId === id))
+    .filter((line): line is PreviewLine => Boolean(line));
+  const first = source[0];
+  const item = context.poItems.find((candidate) => candidate.id === allocation.purchaseOrderItemId);
+  const poItemId = allocation.purchaseOrderItemId ?? null;
+  const poUnit = item && typeof item.unit === "string" ? item.unit : null;
+  const poRate = item ? (finiteNumber(item.rate) ?? null) : null;
+  const ordered = item ? (finiteNumber(item.qty) ?? null) : null;
+  const priorReceived = priorReceivedForItem(context, poItemId);
+
+  const slipQty = finiteNumber(first?.qty) ?? null;
+  const slipUnit = first?.unit ?? null;
+  const slipPrice = finiteNumber(first?.unit_price) ?? null;
+  const slipAmount = finiteNumber(first?.line_amount) ?? null;
+
+  // The slip's unit against the order's unit: this is the question a roll
+  // of mesh against an order in metres asks.
+  const unitDiffers = Boolean(slipUnit && poUnit && !sameReceivingUnit(slipUnit, poUnit));
+  const confirmedQty = finiteNumber(allocation.operatorConfirmation?.quantity);
+  const factor = unitDiffers
+    ? (usableFactor(allocation.factor) ? allocation.factor : null)
+    : (usableFactor(allocation.factor) ? allocation.factor : 1);
+  const qty = slipQty;
+  const unit = slipUnit;
+  const poQty = confirmedQty ?? (factor === null || qty === null ? null : round2(qty * factor));
+
+  const leftOnPo = ordered === null || poQty === null
+    ? null
+    : round2(ordered - priorReceived - bookedForItem(context, poItemId) - poQty);
+
+  const confirmedNet = finiteNumber(allocation.operatorConfirmation?.netAmount);
+  const value = confirmedNet ?? (poQty === null || poRate === null ? null : round2(poQty * poRate));
+
+  const flags: LineRow["flags"] = [];
+  if (unitDiffers) flags.push("unit_differs");
+  if (unitDiffers && factor === null && confirmedQty === null) flags.push("factor_missing");
+  // A price comparison needs the factor: the slip's rate is per slip unit
+  // and the order's is per order unit.
+  if (factor !== null && priceFlagged(context, allocation)) flags.push("price_differs");
+  if (leftOnPo !== null && leftOnPo < 0) flags.push("over_po");
+  if (!guardAgrees(context, allocation)) flags.push("guard_conflict");
+  // A NIL line and a free accessory legitimately have no order line.
+  if (!poItemId && !["not_delivered", "included"].includes(allocation.amountBasis)) flags.push("not_on_po");
+
+  const problem = flags.includes("factor_missing")
+    ? `Enter how many ${poUnit ?? "order unit"} one ${slipUnit ?? "unit"} is`
+    : flags.includes("not_on_po")
+      ? "This line is not on the purchase order. Choose the order line it belongs to."
+      : flags.includes("guard_conflict")
+        ? "The purchase order line and this slip line do not agree. Check which order line this is."
+        : flags.includes("price_differs")
+          ? `The slip price R${slipPrice ?? "?"} differs from the order rate R${poRate ?? "?"}`
+          : flags.includes("over_po")
+            ? "This is more than the purchase order has left."
+            : null;
+
+  return {
+    numbers: allocation.sourceLineIds.map((id) => lineNumbers.get(id)).filter((value): value is number => typeof value === "number").sort((a, b) => a - b),
+    allocationIndex,
+    slipText: source.map((line) => line.description ?? "Unreadable line").join(" + "),
+    slipQty, slipUnit, slipPrice, slipAmount,
+    poItemId, poUnit, poRate, ordered, priorReceived,
+    qty, unit, factor, poQty,
+    price: slipPrice, value, leftOnPo,
+    flags,
+    ready: lineReady(context, preview, allocationIndex) && !flags.includes("factor_missing"),
+    posted: Boolean(allocation.posted),
+    problem,
+  };
+}
+
+/** One row per allocation, in the order the slip printed its lines. */
+export function buildLineRows(context: PreviewContext, preview: ProcessingPreview): LineRow[] {
+  const lineNumbers = new Map(context.lines.map((line, index) => [line.sourceLineId, index + 1]));
+  return preview.allocations.map((allocation, index) => buildRow(context, preview, allocation, index, lineNumbers));
+}
+
+/**
+ * Turn the clerk's edit into the confirmation that books the line.
+ *
+ * The quantity booked is the slip's quantity times the factor, in the
+ * order's unit. A factor of one with a different unit means the order's
+ * unit label is wrong, and the slip's own unit is booked instead. The
+ * reason is never empty: the arithmetic is written down so the next person
+ * can see how the number was reached.
+ */
+export function editToConfirmation(row: LineRow, edit: LineEdit, poUnit: string | null): LineConfirmation {
+  const targetUnit = poUnit ?? row.poUnit ?? null;
+  const slipUnit = edit.slipUnit;
+  const factor = edit.factor;
+  if (factor === null || factor === undefined || !usableFactor(factor))
+    throw Error(`Enter how many ${targetUnit ?? "order unit"} one ${slipUnit} is`);
+
+  const poQty = round2(edit.slipQty * factor);
+  const differs = Boolean(targetUnit && !sameReceivingUnit(slipUnit, targetUnit));
+  // A factor of one with a different unit means the order's unit label is
+  // wrong, so the slip's own unit is what was received.
+  const unitOverride = differs && factor === 1;
+  const unit = differs && !unitOverride ? targetUnit! : slipUnit;
+  const priceEdited = edit.price !== null && edit.price !== undefined && edit.usePoRate !== true;
+
+  const reason = edit.reason?.trim() || [
+    `${edit.slipQty} ${slipUnit} × ${factor} = ${poQty} ${unit}`,
+    ...(priceEdited ? [`Price R${edit.price} instead of PO R${row.poRate ?? "?"}`] : []),
+  ].join("; ");
+
+  return {
+    confirmed: true,
+    poItemId: edit.poItemId,
+    quantity: poQty,
+    unit,
+    ...(unitOverride ? { unitOverride: true } : {}),
+    ...(priceEdited ? { netAmount: round2(poQty * edit.price!) } : { usePoRate: true }),
+    reason,
+  };
+}
diff --git a/src/lib/inbox-three/readiness.ts b/src/lib/inbox-three/readiness.ts
index f5403bc..999bf5b 100644
--- a/src/lib/inbox-three/readiness.ts
+++ b/src/lib/inbox-three/readiness.ts
@@ -143,7 +143,7 @@ function unitAgrees(context: PreviewContext, a: PreviewAllocation): boolean {
  * PO rate plus VAT is not a price problem, and a slip printing the PO rate
  * is not one either.
  */
-function priceFlagged(context: PreviewContext, a: PreviewAllocation): boolean {
+export function priceFlagged(context: PreviewContext, a: PreviewAllocation): boolean {
   const rate = poRateNet(context, a);
   if (rate === null) return false;
   const line = context.lines.find((l) => a.sourceLineIds.includes(l.sourceLineId));