My experience yes. Heat tempering has been an ongoing experiment for me for a couple of years. I wont disagree with someone with more experience than me with it, but I have been tempering early at floor tiller and then again when I see that the tempered wood has been removed. I think I may tiller a bit different than some guys, in that I floor tiller only to get the limbs bending evenly at 4 inches or so, then it's to the short string if possible, long string otherwise. That means I am very heavy when I string it. Lots of wood has to be removed, so I will temper again later. Some guys get it real close during floor tiller which would mean they might not need to temper again. This is white woods primarily, but Osage some as well.