You can get the extended maintenance even after 50K, just cost a bit more. I got mine when I was close to 60K. Cheers.

__________________
-2006 E53 (X5 4.4) Titanium Silver, fully optioned (sports package, premium package, navigation, ride height adjustment, panorama moon roof, rear climate package). Aero kit installed plus set of staggered 20s with Diamaris tyres.