Less than 10fps variation I am not going to bother about. Yours and my F1 were not too far away, so I recon they are somewhere about right.
Think I need to be more accurate with the pellet path through the Skan before I condem it. May well put the rifle in a rest so that it is properly level.
I am not going to go as far as weighing pellets though
You will be pleased to know that I did not shoot your Combro