We too run 3 fume boards with a leaf blower follow up. Usually in the spring and summer pulls (like right now) the honey is not well capped in many supers. Fume boards often won't drive bees off uncapped honey so quite a few have numbers of bees who get blown onto the ground. I don't see much if any loss from blowing bees. In the fall honey harvest most of the honey is capped and with 3 fume boards on a sunny day it is all 3 of us can do to keep up with the fume boards and not much blowing is needed. Using a blower late in the season after the honey flow is over is tantamount to a declaration of war as far as the bees are concerned so pull honey early and pull honey often.
I would be careful using a blower if you have brood in a honey super as you may also have a queen who may get blown out and not find her way home or more likely be killed by the competition where she gets blown out.