Hydraulic pumps;
The fluid from the entire system is cooled by the heat exchangers in the tanks....so there is your requirement for 760kg (to cover the heat exchangers).
The overheat for the EMDP´s is measuring the temperature of the EMDP casings. They will heat up much quicker than the EDP´s due to the reasons Ifixplanes has said.
If you are tooling around with 700kg a side the fluid temperature will most likely rise. If you turn your EMDP´s off.....it will not rise as much.
Thats my take, happy to be corrected.