I think Barnes has missed more penalty's for BHA than Ulloa.
Depends on how you look at it. Ulloa has failed to score 100% of his penalties (50% saved, 50% missed). Barnes has scored 75%* of his, and the other 25% were all on target.
Barnes's penalty record is not as good as Lopez's but neither is it as bad as some people seem to suggest.
(*One was scored on the follow up)