Suggestion is simple, when using icons for charge attacks display the total AP and MP cost below the icons so that we know how much we're going to spend with the current selection. Some Examples:
Infernal Behemoth with no status modifiers and just the base skills for the charge attacks:
Enervate is selected: The selected charge attack will cost 1 AP and 5 MP.
Rage Strike is selected: The selected charge attack will cost 2 AP and 15 MP.
Right now I have nothing but memorization to go by, whereas I believe the drop down menu at least provided some of this information.
UI: Display AP and MP Costs When Using Charge Attack Icons
Re: UI: Display AP and MP Costs When Using Charge Attack Icons
Costs could possibly display on hover.
Re: UI: Display AP and MP Costs When Using Charge Attack Icons
I'm suggesting text below because mobile doesn't have hover. Text below works for both regular and mobile browsers.