What is power supply resolution?
A programmable supply is required to make a production programmer for these PICs, because production verification must be done at both minimum and maximum Vdd for the part.

There are requirements for both accuracy and resolution of the programming, however the document does not actually specify what the tolerances are, just that it must be verified 'at' the minimum and maximum voltages, which is clearly an impossible condition to meet.

It's left up to the implementor whether it's better to fudge the maximum and potentially compromise the programming verification or vice versa (or just aim for the nominal and let the the chips fall where they may, so to speak).