When ticked during a manual assignment, Sprwt looks at every order the customer placed on or after the attribution start date and, for each one that does not already have a commission for this affiliate, calculates the commission using the affiliate's rule (the step is chosen relative to the attribution date) and records it as Unpaid. Orders that already have a commission, or that fall outside all rule steps, are skipped. The confirmation message reports "Backfill: N commission(s) created, M skipped." The created commissions then appear in the Affiliates Report like any other.