You do know that the oil life monitor (OLM) does not monitor the oil, right?
For those who may be unaware of how it works.
Its a computer algorithm that uses engine speed, engine starts, engine temps, engine rpms, and other sensor data as input into computer program, then assigns valves based on severity and counts down to 0% remaining(basic explanation but much more complicated). Basically a vehicle that is driven mostly at normal speeds on the highway will be ideal conditions and take longer to reach 0%. Vehicles driven in stop and go traffic, that are idled a lot, have turned on and off many times in a day will likely see shorter oil change intervals. Anything that stress's the motor also stress the oil and would make it count down faster.
The type of oil has nothing to do with it except in programming of the OLM. Vehicles that come factory filled with synthetic oil, i.e. Corvette and Cadillac will have the OLM set to a higher count than those that don't come with synthetic. Note-GM trucks DO NOT COME with synthetic oil, they come dexos1. Oils can be synthetic blends and meet dexos1 spec's, GM sells them even under the AC Delco brand.