Okay, so if I understand this correctly this ability allows you you spend a standard action in order to gain an extra round, but as a wizard all you would want in another round is your standard action to cast a spell, so you spend a standard action to gain a standard action. How is this worth a feat? (Barring quicken spell like)
I guess you could do sneaky things during the one round that nobody knows happened, but that's it.
I've always ruled it to simply give you another round, and it works well.
Perhaps there could be some clarification as to why it only gives one additional round as Time Stop itself gives a minimum of two to prevent that kind of worthlessness.
I could see it as good for full round spells, such as summon spells. Otherwise, quicken spell like ability would be a very optimum use.