Your daily credit is not truly prorated on reserve. You can have 71 hours of credit (out of 72) with 8 days of reserve left and still only get paid the guarantee of 72 at the end of the month. In fact, you could theoretically be in short call 4 more days and never get called but still get nothing extra. The hours you fly cannot be taken away from you, but each time you fly, the days you have left in reserve become less valuable in terms of hours of credit.

But, on the other hand, if you fly above your guarantee and get 'FULL,' you will get the rest of your reserve days off.