NPP is a shorter-acting ester than deca (though still significantly longer than things like oral winny, var and to a degree, primo), but still helps "lube" the joints because it aromatizes. But that aromatization is what would also contribute to water retention. Because of that still longer ester, I'd probably say save it either for off-season or no later than probably 8 weeks out and switch over to a non-aromatizing cutter. But also w/ the chance var will cause retention. However var is short-acting enough that you would just stop it at ~10 days out and let your body flush the water.
The point is to know the characteristics of the compound you are considering using, particularly its tendency to aromatize or not, its half-life, detection time, and ultimately how it affects your body. And best recommendation ever is don't experiment w/ stuff that you don't have time enough prior to a show date to clear out if the effects can **** up all your work. I'd caveat that again, because the number of women competing in FBB is going to continue dwindling, so there's really no reason to be really aggressive w/ the extremes like using the heavier drugs and more dramatic water manipulation for shows. Reliance should be more & more on the diet and the dial-in to show date.
And just as a note to anyone reading this as part of their research - steroids are the LAST thing you want to go to for desperation attempts to hit a show date. Because of things like each compound's half-life, clearing time and particularly the water-retention response, none of them are really appropriate for last minute "fixes" for something in your prep that didn't come out right. Diuretics are an option for some water manipulation on a very short timeline, but that comes w/a cost. Dumping excessive water can also leave you flat and muddy. Even if you don't have huge muscles, looking flat will kill your detail. Then trying to make up for that by trying to fill out quickly on carbs can just leave you bloated. Literally, moderation in everything. Slow, incremental changes w/ enough time to let your body right itself, e.g. flush water - which means plan your prep, execute your prep, don't doubt your prep. If you feel like you need to go to desperation measures any later than say 10 days out, you might want to look at a later show date. Or make your corrections w/o jumping on drugs to fix it, cuz it won't work.