More issues with the Commerce Ghost:
-sometimes the pref isn't cleared properly (most likely because there's no check for whether or not you bought and got stats). Even if you buy the item and get your substat reward, Mafia sometimes thinks you didn't do anything with it yet. You'd have to clear it manually with a set in that case.
-there's currently also no countdown for charging when it'll next ask you to buy an item, which according to my log is every 10 fights, followed by the substat reward at the end of the next fight. Counts combats rather than victories, so banishes and runs are both eligible to charge up your next ghost purchase task, as well as count as an ended fight for the purpose of awarding substats.