Here is a simple way I look at it.
5000+647x39=30233 after 3 years. You are 30K out from your pocket. or 10k/ year to drive the brand new UDM.
Now if you buy it out right. Let's say 60k for your cost. At the end of 3 years, how much will you get if you decide to sell it? I would think you can at least sell it for 30k PLUS or even 40k for a 3 year old sav.
The thing is BMW hold better value than most others. Now, if it's a ML, I would lease cause if drop it's value so fast.