I use it X-Former Grind quite aggressively, MUCH more than 10% difference. I also do other things in order to get the level of aggression I like. I'll swap tone stacks, turn the power amp hardness WAY up, turn the negative feedback WAY up and anything else I can in order to get the fastest response and most defined attack I can. I'll usually go past where I need it to be and then dial it back a bit.
Sorry for yammering on, long story short, an aggressive X-Former Grind setting is important part of my sound.
I played a Boogie MKII C+ for years along with a highly modded 1981 Marshall JCM 800 and I'm used to, and love playing amps that can bite my head off. \../