you cant get more then 655xx damage in a single hit. Well you can, but it won't show you. The easiest way to prove this is with hagendis hit as that skill is 11 hits. Damage: original hit * 11.

Atm i'm bursting on the wind sheep and on my first mob i get an average of 105k damage (9500*11). This includes a single crit and wit JS. With tripple crits i managed to get over 140k damage.