No, it rounds down. It is only good for destroying your items by repairing them 2-4 times, and only possible in certain circumstances. In fact, it does not fulfill it's original purpose of letting you reduce your item types. It's a major oversight that it only repairs one step, as opposed to the two steps of damage that gear takes in battles. Either way, if you want to repair your items to their original status, you're looking at a conversion rate of 9 to 1, which is much worse than selling the items and rebuying them, and that's even before discounts are factored in.
Just so we all understand what in talking about, if you had a +0 armor, after your battle you should have -2 armor and +0, which is two item types. If you repair the -2s once, you will still have two item types, -1 and +0, which really hasn't helped once. After the next battle, you will have 4 item types, if you did repair once, you will have +0, -1, -2, and -3. If you did not, you would only have three: +0, -2 and -4.
I forgot whether items sell for their base price divided by 5 or by 8, but those numbers are both less than 9.
So, repairing is essentially bad all the time.