Question on this one Nate, we don't use the circular's too often as most of our roofs are wood and we go with chainsaws. We have been taught to lift the blade off the roof a little bit, throttle up to a higher rpm, and then drop the blade back onto the roof to start cutting. Are you saying not to do that or do you mean simply "gunning" it for no reason? Just wanting to clarify.
The saw should also not be "gunned" when not in contact with the roof. Gunning the saw is both dangerous and pointless.