If the tiller was good before you tempered, it should remain good afterwards. If you add reflex while you temper, and I would, you might change the tiller a skosh, but you will pick up some draw weight. Should be able to touch it up and have it right. I have adjusted the setback in one limb while tempering to tweak the tiller as opposed to taking wood off.
Just to clarify, I have adjusted the setback, or recurve, or kinks in one limb to tweak the tiller.