There's a chart on how to bid in the bid packages every month, depending on a 30/31 day month, and how many weeks of vacation you have you generally have to bid on PBS for around 76/78 hrs of credit for 7 vacation days, and around 85 hrs of credit for 14 days. The chart shows how many vacation days vs days in bid period to not work for free. Unfortunately once your line is awarded, it is what it is.