User blog:Baju05/Mixi-max TP bar help

Hi everyone. I need help in explaining the TP bar while a player is in Mixi-max form. Most of the hissatsus while in Mixi-max cost 20 TP. But i notice sometimes the bar goes emty after 2 or 3 uses. Can someone explain how the TP lowers and how make it last longer if possible ?

Thanks in advance. :)