I am personally skeptical about the value of keeping every credit card under 30% of its individual credit limit. While it is incontrovertibly true that FICO punishes you -- sometimes quite harshly -- when you run a credit card up very high toward its limit, I have never seen any evidence that this happens when a card is under 49%. Quite the contrary, there's been a number of people who have seen no score impact at all for CCs in the 50-69% range (as long as their total util was reasonably low). There's a guy who posted an interesting case study of getting some benefit when all his cards crossed to below 49%, and I respect his insight, so he convinced me that 49% is likely a threshold of sorts.
But certainly I would not incur BT fees in pursuit of this probably phantom benefit. Just keep doing what you are doing. Your one card will keep going down and so will your total U. A breakpoint for Total U is supposed to be 8.99%, and it sounds like you may be able to cross that sometime this summer.
Wish the myfico simulator would simulate what happens when a major derog comes off.