From Retention>General Settings in OneCore you can select either default or line item retention types for your expense and revenue retention:
Default retention subtracts the retention amount from the invoice claim amount. For example, if the claim amount is $3,000 and the work retention amount is $150, this is how it would be shown in Xero:
Line item retention shows a separate line item for the retention amount, which is subtracted from the claim amount. This is how it would be shown in Xero:
