Hehe, forgot about this post guys, the placard calls for P235/75(XL) with inflation at 40psi.
According to tirerack, it is a tire with a "D" load range.(I think, it is down at the moment, so I cant double check) Which I guess according to ford and michelin is "XL" on "passenger" tires.(XL may be a slightly lower rating than "D", as D is usually on LT tires, not Passenger.) Now the LT tires we asked for weren't rated better, but either way the LT's are a more heavy duty tire as you know.
Tires on the van now are all BFG's P235/75@35-36psi.. 30k miles later the fronts are wearing fine, replaced one 10k miles ago as it had a small tear in it, probably from my spirited cornering on slightly sub par tires. I don't do it anymore though, and the rears were just replaced about 8k ago. We do not load this vehicle to the max and it is only a 7 passenger model, the current tires are shy of the previous tires weight rating by 80lbs.
Not all walmart service center people are idiots. The one here where we live now actually asked if we wanted the LT's on it, however we chose not to because we did not have the extra 55 dollars and they had to be changed. It was better than completely bald tires.