Ok here's my idea
When you powerup you regain ki, and now its at max, no reason to use it anymore till your ki drops again right? Well lets stay that if you keep holding down the powerup button when your ki is fully charged, you'll gain pl, but at a very very slow rate. The rate would be high enough that it is helpful when you need a small pl raiser... Then when you trans the rate will go up by like, 5 percent faster on first trans. Second trans will go up 8 percent faster. While third trans would be 10 percent faster. and so on...
When you powerup you regain ki, and now its at max, no reason to use it anymore till your ki drops again right? Well lets stay that if you keep holding down the powerup button when your ki is fully charged, you'll gain pl, but at a very very slow rate. The rate would be high enough that it is helpful when you need a small pl raiser... Then when you trans the rate will go up by like, 5 percent faster on first trans. Second trans will go up 8 percent faster. While third trans would be 10 percent faster. and so on...