The owner's manual states that a transmission fluid and filter change is not necessary. Specifically, it states: "Fluid And Filter Changes- Under normal operating conditions, the fluid installed at the factory will provide satisfactory lubrication for the life of the vehicle. Routine fluid and filter changes are not required. However, change the fluid and filter if the fluid becomes contaminated (with water, etc.), or if the transmission is disassembled for any reason." If you still feel that it is necessary to do it after a specific number of miles, be prepared for a huge dealer transmission service bill. It is around $1,000 with around $400 of that being the integral filter/pan assembly (fluid is $33 qt. or more).
I did my 850re @ 31k . The fluid wasn't too bad looking. The old pan with the built in magnets had some metal powder on them. I figured better safe than sorry. But I guess if you're some that leases the vehicle and planned on returning it, you would be wasting your money.
