That's right, but it's generally more efficient anyways to sell your 0 star ball and replace it with a new 1 star ball from the shop.
But what if the 0 star teir 1 ball had lots of stats you want to keep!? Then that means in teir 2, selling the ball to get a 1 star replacement is bad.
so don't do it then..?
It again depends. Do what you think will help you in the long run- its always better to do that, especially focusing on stacking abilities-
