When I start up my MCS the center LED will obviously display the mileage of my car(which stays there as long as my car is running) but right above that a message appears, for awhile I noticed it saying "mlg 16000" , then it dissapeares, now the same message appears but it's "mlg 15000" , I'm thinking it's counting down the mileage until my car requires its next service call, am I correct.

 

Yeah, usually it also shows a symbol in the bigger lcd screen on the tach that looks like a car on a lift. It does indicate mileage til the next service, and I know for my car there's also the estimated date shown too