(RMXP) HELP WITH CUSTOM STATES - (SCRIPT NEEDED?)

Hello! I've been wondering how to make a custom state that increases stats but by a FINITE, CONCRETE amount instead of increasing them by percentages. (So, instead of 150% PDEF, the state can have a increase of +4 PDEF, and stuff like that.)

I'm using RPG Maker XP, BTW.

So... I would apprecciate if someone could point me in the right direction!
I have been searching in google but without much success...
Thanks in advance!