They should not count your challenge if you were correct, each team could still get 2 per half but if the call is reversed due to a challenge, that challenge is given back to the team. So you can challenge as many penalties as the officials blew before the challenge. Eventually the league would have to do something to make the officials accountable for their blown calls as the number of calls overturned would lengthen the game by as much as an hr on average, and if the NFL wants to shorten that they just have to get the calls right and quit makin crap up.