Hi Ontrose,
good question :-D
I checked with the code.. Every creep has a built in drop chance, and this chance of the creep is increased by the aura.
So the effect kicks in before any tower drop chance multiplier.
Well that opens up a few tactics with the upcoming patch ^^
So lets say every creep got 10% inherent dropchance.
Then you gain lets say 100% bonus by the Widow. Which effectively sets the dropchance to 20%.
Then the Towereffect (Pots, items etc) come in with 400%.
Which means an 80% total dropchance.
This is the way its calculated right? (well, the value are just picked for easy caluclation ^^ and there might be other factors like rich, which unit type [boss/air/mass....] which are not taken into account but should be calculated even before the widow aura right?)
Like i said this calculation is just an example without real values and probably softcaps (dont know if the wavecounter adds in anything here besides prevent legendarys on round 1 ^^).
Any flaws of logic in there?