Same method as above and I get drops every four to five toc. Yes I get a lot of helmets but I've also found jade rabbit, suros, a sniper (who's name escapes me - extended zoom when crouched), invective, new fusion rifle, chest piece and supercell. All total 65 toc and maybe 10-13 exotics since the patch. Also I believe the debuff is for the use of the coin. If you pop one kill the ultra and immediately pop another at the start of the next mission your chances will drop. This is only my experience. Also I generally wait ten minutes between use each toc. Hope this helps.

I find that using them sparingly works better. And I've had the best luck on 36 strike list. Used 3 coins today and got Helm Saint 14.