Putting around 5 levels worth of APs into HP for the next 5 levels w/o HP-washing?

Yeah, if all you care about is getting your hp up enough to ht, then start dumping ap into hp, also a few shouldn't make you very much weaker if its just a few levels, but remember that for every 8-11 or so luk ( depending on some other factors ) does equal about one watk so if you're worried about that think of it that way.