'Retainage %' is the percentage of the invoice amount that a client holds back against the verification and quality of work completed. The accumulated retainage is typically paid after the verification is done. Core computes the invoice amount as:
Amount Due = Services Billed + Expenses Billed + Taxes – Applied Retainer – Discount – Retainage.
For example, if Total Bill Amount = $1000, Calculated Retainage = $50,
Amount Due After Retainage = $1000 - $50 = $950