Yea I'm the same as Richard. I typically mash in the low 150's, and when aiming for 168, I typically bring it between 182 and 190, depending on size of grain bill. If I'm using 8 pounds of grain its around 182, and if I'm using 13 or 14 pounds of grain it's up towards 190.
It seems I can always get between 165 and 170. I've only overshot once by a couple degrees with no ill effects.