Hero damage - help with my max dmg potential

Ahhhh....I did'nt know about the damage penalty. I am 2 levels lower than the mob. I guess its either the damage penalty or wrong calculation of critical that probably explains it.

Also, good idea about looking at my highest non-crit damage. I will do that as well after I factor in the damage penalty to see if crit is being calculated wrong.

Thanks for your help, off to find damage penalty formula.