It is important to note that various PDC brands will have small differences due to slightly different calculations in the PDC. These calculations are called the decompression algorithm. Also, remember that after your first dive of the day, the times will be significantly reduced. This is because the PDC is calculating and considering your accrued nitrogen from the first dive.
Below are examples from an air PDC that has not dived for 24 hours and is showing the dive planning pages in metric and imperial. (Note small differences as depths do not exactly equate.) These are the NDLs according to this PDC. If we had already dived on this PDC today, it would calculate new reduced NDLs.