Can you extend a CPO to get that 7th year?

I am very close to buying a CPO 335d and I am working to either bundle in a platinum 7/100 or have it CPOed. With the CPO you get essentially 6/100 gold, my question is: can you extend the cpo to make it 7/100?

I'd like to make the sale of the car contingent on warranty/wheel n tire pricing instead of saving this discussion/decision (with the finance person) to after the purchase agreement.

BTW, from what I am reading, the 7/100 platinum is definitely better, but not sure about cost overall. However, their first quote was for $3,400 to do the CPO which includes tires that they wouldn't otherwise put on the car.