In which case, you could do one of two things:
1) Put the following in the formula instead:
x is the percentage you want to heal.
2) Copy and paste the function into a JS text file in the plugins folder, then when you add it to the Plugin Manager, you should be able to use the function in the skill's formula, like so:
Code:
b.hp + Math.toPercent(b.mhp, x)
This would be just a waste, however, as it's just one function (the current version of my
Extra Functions Add-On plugin is private at the moment).
EDIT: I forgot that you can copy and paste the method in a Script event command (set to autorun) somewhere at the beginning of the game; it should then be compatible throughout.
Both methods heal a percentage of the target's maximum HP (rounded up a bit). You can also use this format for other damage types. Obviously, the first method is the simplest and most effective for your purposes.
@Mr. Trivel wrote an
excellent Damage Formulas tutorial that will help you a great deal.