Yes, could be due to the averaging over time. The averaging time is constantly increasing.
Yes, I am trying to decipher that too. I started mining using just one computer and it shows 400h/s on computer but only 35 h/s on optiminer. Unless his table shows 10 times less than what h/s really is, I am missing something here.
if Paddy321 is running 650h/s for 1 hour, optiminer should show close to it. Average s hould be around that speed after 3 minutes, not just after 1 hour.