Hey.
1. In this case you gain the MP when damaged by a skill.
2. They can both exist.
3. Hmm, you can technically adjust the following values if you want to change things mid-game.
Toby_Yasha.Param.Charge_MPFormula_Actor
Toby_Yasha.Param.TurnEnd_MPFormula_Actor
Toby_Yasha.Param.Initial_MPFormula_Actor
Toby_Yasha.Param.Charge_MPFormula_Enemy
Toby_Yasha.Param.TurnEnd_MPFormula_Enemy
Toby_Yasha.Param.Initial_MPFormula_Enemy
Example:
Increase MP gained by 10, upon being attacked.
Toby_Yasha.Param.Charge_MPFormula_Actor += 10;
Decrease MP gained by variable 5, on turn end.
Toby_Yasha.Param.TurnEnd_MPFormula_Actor -= $gameVariables.value(5);
Honestly, this is a pretty old plugin and in its current state it could mess with other plugins in unintended ways.
I need to push an update to get it up to speed if you don't mind.