some miss conceptions, but then it all resonably new knowledge to me anyway
as 400HPONGAS, 350RRC and Mick_Marsh are on the money.
The fill levels are only a couple of cm difference in height so there is really no problem there. Better if a balance pipe is fitted from filler to filler, that way the gear box is never overfulling, that is if it is needed?
maybe check in you have your wading plug in the bell housing you could be losing a bit of oil from the pump cover, some time a bit hard to tell if your rear seal is a bit tired as well

