Motordavid (and others)- thanks for the replies. Perhaps I could have been clearer. I bought my 2004 X5 from a dealer second hand as a CPO car with about 19K miles. I now have 48K miles and the original factory warranty and included full maintenance are about to expire. The CPO portion will continue until 100K miles or 5 years whichever comes first.
So I am OK here. Looks like I will purchase the Extended Maintenance to 100K for $1395 US. That seems a good deal as the 60K maintenance coming up would be nearly $900 US and I am sure I'll need at least 1 set of brakes and rotors in the next 50K, probably 2 plus wiper blades, filters etc!
The core of my question was whether I should consider any other coverage beyond the CPO and extending the full maintenance. 3rd parties aside, it appears that the BMW offering is for people owning an original purchase car and wanting what I already have as a CPO customer so that is out. Looks like I have as much as you can have in coverage from BMW short of buying another CPO. This is my 4th CPO car and aside from the wrecked 740i I was sold and returned, it seems the best way to buy these cars.
Thanks again. Let me know if I have something wrong here.