Can the Big Blind Player Post More than the Current Big Blind?
In a tournament, "blinds" are set by formula, based on the number of rounds that have elapsed. So the big blind amount in this instance is 400.

It's a LIVE blind, which means that the big blind can raise, but only after others have had a chance to do so. That's the disadvantage of being a big blind. 

Essentially, he raises the little blind from 200 to 400, and then again at the end of the round (if no one else has raised 150 or more). But he can't "protect" his blind by raising the whole 550 the first time.