Yeah, something like that. Though I do have to warn you, both players and enemies level up as the game goes along. So using static numbers would scale rather poorly for your abilities in the long run. Think of something like, SPI-7 for high effect, SPI-1 for low effect. 

And I'm not implying you are a godmoder or anything, but that these kinds of stats help us cover some of the weaknesses of the 'by ear' method ;p