Invoice Underpayment

Overview

Invoice underpayment occurs when the value received and accepted for an invoice is below the amount due. It can result from customer error, exchange withdrawal fees, transfer-tax tokens, rounding, partial payment, quote expiry, or intentional installment. The system should compare the exact received amount with the expected amount and an explicit tolerance rather than using a generic unpaid flag. When implementing Invoice Underpayment alongside Underpayment Recovery, implementations should preserve the issued version, due balance, denomination, tax treatment, payment instructions, and every later adjustment or settlement event.

A small crypto shortfall can be accepted within an underpayment coverage policy. The invoice can be marked paid while the difference is recorded as an allowed adjustment or fee.

A material shortfall can leave a remaining balance, request an additional payment, permit mixed payment, or require manual acceptance. The new request should not double-count the first transaction.

Fiat value comparison depends on the agreed quote. Revaluing the received crypto later can incorrectly turn an underpayment into an overpayment or the reverse.

Risks include abuse through repeated small shortages, transfer fees misattributed to the merchant, duplicate completion, inconsistent tax, and customer confusion.

Systems should store expected and received amounts, asset, rate, tolerance, remaining balance, decision, additional payment, manual approver, and final accounting.

The workflow for Invoice Underpayment commonly touches Underpayment Coverage and Underpayment Recovery. Documenting those handoffs keeps duplicate events, delayed updates, and manual corrections for Invoice Underpayment traceable to the correct object.

For Invoice Underpayment, version control is essential. When Invoice Underpayment interacts with Underpayment Coverage, corrections should use a replacement, credit note, cancellation, or auditable adjustment linked to the original record instead of overwriting historical values. In the relationship between Invoice Underpayment and Underpayment Recovery, exports and reports should reproduce the document as it existed at issuance, including the customer, tax rule, exchange-rate basis, payment terms, and payment instructions that were actually communicated.