On Steven Ellis' online book he said that he lost 90 thousand dollars or so because he lost his velocity from a year to another.
He lost something like 5mph or so and couldn't find out what was the problem. Then he said that he saw a pitching coach who had been with him for a looong time and they found what the problem was.
His stride was some inches short. Maybe this is also your "flaw". Ask your coach if he can notice anything wrong with your stride.