You are correct, they had 100 and now its 50. Still, 50 delegates is a not that much compared to Super Tuesday which Romney is likely to lose.
You are right, 50 is not that much. I’m not sure even the professionals know for sure how this plays with delegates yet.
For example, one little state I know of with more than three times the delegates of Florida, has not even been allowed to set its primary date yet - and by rights should also still be a winner-take-all state sure to go Gingrich, but appears to have had its voting strength diluted by being forced to go proportional because of the unsettled primary date chaos!