Ken, I haven't checked to see if there is a part number difference between the pans, but I would imagine they are actually the same pan. Even on the EJ25s I've owned there were slight differences in the amount of oil called for in the manual, but only like 0.1 or 0.2 quarts, and you also had the fiasco of having a "full" dot and then a half-moon notch on the dipstick which was "full hot"; the manual claimed that when the oil was hot, it may expand all the way up to the notch yet return to the dot when cool. I've never seen this on any other manufacturer, and even Subaru's H6s never had it (at least on the Tribeca I owned). Since I've never measured the volume of the oil pan off the engine, I don't know how close the oil sits to the rotating assembly; I'd assume that even at the highest recommended level it is still well clear of the crank and rods. Subaru may simply allow a hair more fill level for things like you posit- a high-revving, vehicle attitude-altering off road trip may get dangerously low in the sump with the lower fill amount and risk air introduction which would obviously be really bad. It may have to do with the boxer design since oil in the engine may pool in one head when the vehicle is laid over. So they fill the pan a hair more to give a safety cushion. Just a guess of course but it seems logical.