Why did New Jersey cast the final votes needed to boost Romney over the edge?

Instead of defering their votes so that either Michigan or Massachusetts, Mitt Romney's home state, of having the honor of doing so? In past conventions it has usually been the custom for states, not being the home of the presumptive nominee, to abstain from anouncing their votes if they would have boost them over the limit.

I remember watching them do that with Bill clinton and George Bush.