When setting a bounty on a question, I'm given several options. One of those options is "One or more of the answers is exemplary and worthy of an additional bounty". I chose that option, and there's a bounty button besides every answer. When I click the answer I want to award the bounty to, it tells me I have to wait 23 hours.
I understand the reasoning behind forcing a wait when the bounty is set to attract more answers, but when one has already been chosen, then what's the point? Paraphrasing @nhinkle on the Ask a Mod room, "I guess the idea is that mayyyybe a WAY MUCH BETTER answer will magically come along. which in practice I doubt never ever happens."
So, I think for the very specific case of awarding a bounty to an existing question, the 23 hour limit should be removed.