I would guess a plugged line or lines for the charcoal canister.
However, if you fill up from a station with a large underground storage tank (50F) and the air temp is more like 100F, believe me, that gasoline "grows" quite a bit. What you are seeing is typical of the expansion I would expect.
Don't know what kind of filler nozzles you all have, but the ones up here won't go into a Benz tank very far -- the diesel is the worst, it is the old large diameter one -- so you may be overfilling.
Run the fuel in as fast as it will go, not slowly. This will trap some air in the tank and evap system, stopping the pump "early" and leaving you more room in the tank.
I'd also try to fill up in the evening on the way home, so that you drive some out before you park it.
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!