Someone's math sucks. :|
That's only counting the 1430 AP you spent. However, had you left it at F rank, you'd be 1430 ahead. So in order for it to be worth it, you'd have to gain back all the AP you spent as well as catch up to where F rank would be. Given the roughly 500 seconds difference, it takes a considerable time to catch up.
If you play for any amount of time less than a year, rank F will benefit you the most. If you want to play onwards of 2 years on the same character, then rank A will definitely be the way to go.