Video Replay in Playoffs

During the series between the Texas Rangers and the New York Yankees, there were back to back homeruns.  Both were controversial.  The Yankees hit a homerun that the outfielder could have robbed, but a few fans got in the way of the outfielder and ended up knocking his glove away from the ball.  The umpire ruled it a homerun and based on that they couldn't go back and review it.  Although I do not understand that, and I believe that it should have been reviewed.  If the game would have come down to a one run win by the Yankees, I would have been upset by this one instance.  But it didn't end up mattering.  But the next at bat for the Yankees, another home run was hit.  The umpire ruled it a homerun again.  But when they replayed it on tv you could clearly tell that it went foul.  They ended up reviewing this and ruled it a foul ball.  What I don't understand is how they can pick and choose which plays can be reviewed and which can't.  Clearly both should have been reviewed.  I am not sure if the first one would have been overturned, but the fact that they ignored it was wrong, in my opinion.  If you are going to review one, review any plays that are even close.  Just to make the right call.  If the evidence withstands the review then that's fine with me, but if it needs to be overturned then review it.