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A payment receipt can produce one payment complement, or REP, with one or many related parent invoices. Lambda includes eligible PPD parents, omits PUE parents, and stamps only when the complete remaining REP is consistent.

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Resolve each parent

Lambda resolves parent evidence in this order:
  1. A matching Lambda income invoice using the CargoWise DataSource/Key.
  2. An embedded sibling income invoice carried by the receipt.
  3. A dependency wait when the intended parent is known but is missing or not stamped.
An unstamped parent moves the receipt to Waiting for parent invoice. When the parent arrives or gets a SAT UUID, Lambda continues the same receipt automatically.

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Decide which parents belong

Each parent is classified from direct PUE or PPD evidence, date inference, or the optional REP eligibility window. Lambda does not stamp a partial REP by silently dropping a failed PPD parent.

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REP eligibility window

The optional REP eligibility window can treat a parent as PUE when the payment arrives close to the parent’s CargoWise PostDate:
  1. Lambda reads the parent’s PostDate.
  2. It adds Window (days) using Mexico City calendar days.
  3. It compares that cutoff with the day Lambda received the payment.
  4. A payment received on or before the cutoff omits that parent as PUE.
  5. A payment received after the cutoff includes that parent as PPD when reconciliation succeeds.
Lambda freezes the setting, reference day, cutoff, and result with the payment intent. A later settings change does not rewrite an in-flight or historical REP. See Settings for the available controls. When the window is disabled, Lambda uses the parent’s direct or inferred PUE or PPD evidence.

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Installments and balances

For every related document, Lambda verifies:
  • the parent SAT UUID and document currency
  • the previous balance
  • the amount paid in document currency
  • the remaining balance
  • the installment number and earlier installment history
The balance chain must stay consistent across all earlier REPs. A payment cannot exceed the current unpaid balance. A receipt with several parents keeps a separate chain for each parent.

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Currency

Cross-currency receipts use CargoWise payment-time MXN evidence and the payment exchange rate. Lambda derives TipoCambioP and EquivalenciaDR, applies controlled precision, and verifies the stamped complement after issuance. See Currency for the formulas and worked examples.

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Exchange-difference lines

CargoWise can add lines with code EXX to represent an exchange difference. These lines adjust the accounting value but do not represent money applied to a SAT related document. Lambda excludes EXX lines from the REP. Ordinary PPD allocations on the same receipt still reconcile and stamp, and the EXX values remain part of CargoWise accounting truth.