aqua puss absolutely has a volume drop, thats why I got rid of mineAqua puss has no volume drop! Thst was the first version of the supa puss.
The only issue with the aqua puss for me (which isn't even an issue) is if you use a ridiculous amount of volume boost into it then it compresses, but that's only with an ungodly amount of boost, like an amount you'd probably never use. If this is somehow an issue for you then use the aqua puss before your overdrives and boosts, that's what it says to do in the manual.
Love that pedal, pretty much have it on all the time.