[2k3] Buff troubles

What I have is a series of skills that Imbues the user with the power of the designated animal's powers. I've looked through the conditions and the skills and I can't do it the way I want.

Can anyone think of a way to use switches or common events to satisfy the conditions of let's say [strngth] + 10%, while also [Defence] - 10%, and then it would have to wait x amount of turns and bring those stats back down to their original values. Or if that won't work, they can go on till the end of the battle, and then reset. I'll be posting my attempts later on today, so ANY kind of help would be nice. Either post here or e-mail AvengedSoul0710@hotmail.com.

You'll recieve a special place in my heart and in my credits

Well here's what I've done so far.

1) I have a variable set to the Hero's attack perameter.
2) I take that variable and multiply it by 0.1 (for 10%)
3) That variable, which is now 10% of his attack is added to another variable that is his base attack value
4) his attack is then set as this variable.

This is where my problem comes in... i can't for the life of me figure out how I'll make it go back to it's original value after the battle, or after a set amount of turns.
What I can do is set it on a literal timer, but that is a little dumb to me, cause for the 2 or so minutes it's on, you might be watching an enemies overly-epic super move lol.

Well, how many different types do you need? I think it'd probably be easier to use conditions which doubles a certain stat (or halves it), and then inflict that condition on the player. This makes for a far more powerful effect than just 10%, though.

Alternatively, you could make an event before a battle which stores your current attack power, use a battle page to calculate your attack power, add 10% to it, increase your base attack power by that amount, then after the battle, remove that increased amount. You do have to be a bit careful with that method, like not accidently removing/adding extra attack after the battle. Also, don't just set it to the attack power you had previously as you might have gained a level.