Yes, that's true This is because traffic on the way back in will either have to be put on vlan 10 or 20, so that means half of your return traffic will not go the right way. Since this port is more-or-less a trunk port its PVID doesn't matter as all traffic recieved on it theoretically should be tagged, so a PVID will not do anything hence leaving it at a default of 1 is preferred. On the way out of the switch the tag will stay on. Tags HP.
nest...