It deletes psarc95.zip. However you stated that the best practice was to have the same number of zips than sets, right? So in cases where a set was formed of merged roms (natodefa and which other?), CMP would want all of them in the set even if they were unneeded. I agree with this part ^_^

So, then there should be an exception for "Mark NoDumps as Unneeded", and it's when a set has its only roms as nodumps, apparently only psarc95 falls in that category.

I guess you already noticed this problem and probably it's in your to-do list, but just in case I'm mentioning it.

Pi - Every Precious Dream and Vision Underneath the Stars
Arcade news, emulator archives and gamelists at CAESAR