Board Thread:General Discussion/@comment-1487677-20160906223325/@comment-28044177-20160907015731

Word has it that Love didn't originally come back to the Gotei during the first timeskip because he didn't want to give up reading his manga(of course this was only stated in Death Saves The Strawberry, so that take what you will). So it's probably the same reason why he didn't take up the position this time either. But it's always possible that Iba was close to being Captain-level before the timeskip anyways.