What do you mean rock it back and forth? like turn the crank back and forth? Dont you only move it a few inches on the direction of the motors rotation?

Also the main concern here is if i will be able to do this without having to take the timing cover off, shouldnt i be able to get a socket though the hole where the plug is and just do it with everything else on?? The people at the dealer and at other shops tell me no, but i am wondering if they are bs'ing me cuz i can see the plug, and i am pretty sure i can get it loose lol...

I was kinda interested in taking the valve cover off to check the condition of the belt, i imation if it was to loose it may have been rubbing up againt the side of the vavle cover causing severe wear, so i just wanna check... btw is there a possibility of wear from it being to tight/loose? and how else should i check for these signs?

Thanks