I have the same problem. I do ok with it, but only because sometimes I'm at the top of the stack. It's too expensive to be a good moneymaker. When I eventually get a Patton, I'll likely move my T20 crew to that and sell the 20. For me, the only purpose it serves is a path to the Pershing(which was worth it) and Med tank crew training. If get stuck in a 9/10 battle, I usually snipe, protect arty, or do base defense.