i have the same problem ....my situation is quite complicated though...i have a opt EAD since july of 2014 to july 24 of 2015 so my opt is about to expire...since i was in STEM i was able to apply for extension which i have already paid (its already been 75 days but still havent got any approval yet) and my extension of opt ead is till dec of 2016 ( ironically when TPS ends ) . since i already paid for opt extension i am not sure if i should apply for TPS or should i just stay in my OPT status and continue working. But i do want to change my status to TPS but since i already paid that 380 dollars for my extension i dont want to pay another 380 for EAD ( i am well aware of the fact that TPS  cost 515 with EAD ) . is there any way i could change my OPT EAD to TPS EAD without paying that extra 380??????