Moser 8 3/4 housing is a Ford

I can't see how they save money, the 8 3/4 cost as much as a 9" ford for the diff. 9" is a nodular case, do they even sell a std case ? My buddy just bought a 9" diff from them N case, Detroit locker, 4:11 gear set up ready to go I think w/shipping $1300. A 8 3/4" diff with a dana power lock is what $1375.00 from Dr diff ?