I let mine get to temp, but I see no real issue with not doing so when using a thermostatically controlled unit. It’s not the same as trying to stabilize a ceramic cooker or a huge offset cooker which requires some adjustments and tinkering. You set the temp and you walk away. Done. Either way, you certainly will never ever be able to discern between a pork butt done one way or the other. If you think you can tell the difference, I call bologna. Again, I’m in the habit of letting it reach set temp, but I can’t possibly imagine it makes a hill of beans difference really. It’s thermostatically controlled for crying out loud. That’s why the pellet grill is wildly popular. You do need to make sure the unit is heated up enough to meet the preheat criteria. So hot (100 I think) in so many minutes. Maybe not put it on before, but all the way heated, meh.