Synthetic invoice reconciliation: identical net lines, two different tax totals

Invented inputs, not an invoice or tax recommendation

Use three distinct synthetic lines A, B and C, each quantity one and net amount 0.03 in an invented GBP calculation. Assume 20% solely for arithmetic and nonnegative half-up rounding to two decimals. Compare two hypothetical policies: round tax per line before summing, or sum unrounded tax and then round once. This is a worked specification, not a tested accounting connector, customer result or determination of lawful tax treatment.

If the matrix is wider than the box, scroll horizontally to read every column. Keyboard: focus the matrix and use Left/Right.

line | net  | unrounded tax | half-up line tax
A    | 0.03 | 0.006         | 0.01
B    | 0.03 | 0.006         | 0.01
C    | 0.03 | 0.006         | 0.01

net total                           = 0.09
policy L: sum rounded line tax       = 0.03; gross = 0.12
policy I: round total tax 0.018 once = 0.02; gross = 0.11
difference                          = 0.01

Reconcile components before accepting the total

Both hypothetical outputs retain three lines and 0.09 net. They disagree on tax and gross because their declared boundaries differ. Label each comparison with the policy, line identity and net/tax/gross components. A one-cent tolerance can hide a real policy mismatch; agreeing a tolerance does not choose the lawful policy or justify changing stored values.

• The finance owner or adviser confirms the applicable policy and rates before implementation.
• A source formula and destination calculation must be compared under that same approved policy.
• Do not infer line tax from a rounded grand total or add a balancing line without agreement.

What was actually exercised

The draft's mechanical evidence independently recomputes this arithmetic with integer rational values. That verifies the numbers only. No Sheet formula, tax engine, API, database, connector or posted invoice was exercised, and neither rounding policy is self-approved as accounting advice. HMRC guidance is UK-specific and distinguishes businesses and calculation methods; do not import this hypothetical half-up choice into a live setup.

• Negative adjustments, discounts, mixed rates, exchange rates and legal invoice requirements are outside this example.

Use the existing offer only for its eligible mapping job

If an approved net or tax field is simply missing, the existing £145 Sheets-to-Xero mapping service may fit its working trigger, five-field ceiling and authorised disposable draft. Resolving tax-policy disagreement, configuring tax, adding a calculation engine or correcting past invoices is not included. Free official guidance, your existing integrator and finance adviser are alternatives. Send invented component expectations and the missing field, never actual invoices, tax records or credentials. The price is untested; payment follows agreed checks and sign-off.