Introduction for A/R Offsets
The accounts receivable offsets section provides for application of outstanding CREDITS and PREPAYMENTS against open invoices.
 

An A/R offset will NOT create a transaction in the GL.  The offset itself has NO impact on the general ledger. It shifts the funds according to the way that the Credit memo and Receivable were established. See attached spreadsheet, each transaction involved from shipping and invoicing through credit memo and offset to check deposit are tracked.