Update: just picked up my uncle's Rolex from the RSC. In the end they said the rotor and balance no need to be changed. So the cost of the service was 1.9k+. I did ask them what parts were changed in this service and they took a picture of the parts for me:
Note on the dial: during the service the technician did some boo-boo and somehow damaged the dial. So they replaced the dial FOC.