Does anyone have experience with oil change and inspection of leased vehicle?

My question is addressed to leasing vehicle drivers who did not have their service at Seat. My Cupra Ateca has to change oil in about 3 weeks, according to AI, has almost 20,000 km on the clock. I had an offer from my car dealership made, 273.- € only for oil changes. I find the liter price of motor oil around 25.- € really happy. He also does not allow to bring his own oil. Free workshops do this for half. Has one of you done this before and there were problems with d he return of the leasing car