In the rules for hero mastery it says that 100% needs to finish within the 3x time bonus. However, its seemingly impossible to collect every coin and finish in the 3x time bonus. Should rules be changed to compensate for this, disregarding the 3x rule?

Yea I'm pretty sure all Mei courses are impossible to 100% within 3X. She'll be the only exception (so far) that we can finish within 2X for the 100% category. I'll add it to the rules