as far as i know, 6x80 can only set the maximum discharge rate. The actual discharge rate will be determined dynamically by the charger. with some simple calc 5000/60/60=1.38 mah/s, so if yr charger took 3s per mah, it should be discharging at around 1.2A
I am also using 6x80c, I found the max achieveable discharge rate for LIPO only around 2 to 2.2A. 5A max discharge rate may only apply to NiMH batteries or if it actually depands on other factors I am not sure.