When you submit a "payment process request", you can enable the Apply credits up to zero amount payment option. Enabling the option causes the payment process to apply credits when the credits reduce the payment amount below zero.
The following scenario illustrate the impact of this option.
Credit Amount Greater Than Invoice Amount
An invoice for 200 USD and a credit memo for 225 USD are due for payment.
The following tabledescribes the payment processing that occurs based on the setting for the Apply credits up to zero amount payment option.
Assume that the "Apply Credits Up to Zero Amount" option is enabled.
Payment processing applies 200 USD of the credit memo to the invoice and creates a payment for 0 USD. The remaining credit is 25 USD.
References:https://fusionhelp.oracle.com/helpPortal/topic/TopicId_P_9F438E13CC89BA0CE040D30A68816F77

User-Defined Validation That Checks a Specific Condition and Value

References:https://docs.oracle.com/cloud/farel9/financialscs_gs/FAIPP/F1469799AN17B6B.htm

Define intercompany system options to set up intercompany processing rules at the enterprise level, based on your specific business needs.
Minimum Transaction Amount
The minimum transaction amount represents a minimum threshold intercompany transaction amount, and prevents the submission of immaterial transactions for small amounts, which are non-value added. In order to implement this rule, you must select a minimum transaction currency for processing intercompany transactions. These two system options must be related to ensure that when comparing a transaction amount to the minimum transaction amount, the two numbers are entered in the same currency, allowing for an accurate comparison.
References:https://docs.oracle.com/cd/E48434_01/fusionapps.1118/e49599/F1110451AN99BEF.htm