From what I gather across bimmer forums, alot of dealers don't replace rotors when brake jobs are done under free-maintenance. No surprise there since BMW seems in belt tightening mode.

So fmk is this brake job under free maintenance or you are paying for it?

As far as X5, I did a measurement with caliper on my old rotors and they are definitely at the margin when the pads are gone; with turning I bet it'll be under min. thickness.