So something odd is going on; I noticed last night that I was two sets of ampies short of what I should have earned. Just now, starting with 528 neckties, I use 60 (3 sets of 20) to kill the L.50 boss...but afterwards I now have 408 neckties. Somehow it used double the amount than should have been the case. Anyone else experiencing this?

edit: it isn't happening every time. The next six runs of 60 were fine. I started with 528 and should have had 8 sets of ampies, but only ended up with 7.