just an FYI since i’m about to return a BMW, there’s a window to be eligible for the credit. The newly leased BMW has to be within 2 mo of turning in the old BMW lease up to 6 mo after you turned in your old BMW lease. So if you take out a new BMW lease 3 months prior to turning in your old lease, technically you’re not eligible for the unused mileage credit.
The same goes for being eligible to waive the disposition fee. The same 8 months window applies.