Commercial svc. on 6.4L

Curious..meet a guy today who has 06 6L F450 who travels alot hauling rodeo horses etc. Said he was told by dealer when looking at 6.4L that only FMC dealer could svc. it & no one else. /ubbthreads/images/graemlins/shrug.gif

Didn't sound right to me. He is commercial, but still ???