The OLM is NOT a timer.
It is a mathematical formula, an algorithm.
Uses many inputs to calculate oil life.
Engine RPMs, engine temps, etc etc.
There was an issue in the 09s and 2010.
GM recalibrated the OLM and the max miles is now limited to about 7500 miles now.
the cars from 2012 or so and up-- require DEXOS compliant oil.
Most of which nowadays are SEMI SYNTHETIC.
I really doubt the dealer is giving you FULL synthetic- unless youre paying extra for it.
Most likely youre getting the Semi syn.
On my 2013- 3.6, I ran a bunch of used oil analysis to test the OLM.
Every time I increased the mileage/OLM % and had oil analyzed.
I was using Pennzoil Platinum Full Synthetic.
Each time the oil came back in good shape for the miles.
Eventually I ran a test with 0% OLM (it was 6500 or 7000) miles on oil.
Analysis came back with the oil still having life left.
So I trust my OLM and change oil when it hits 0%.
Now-- remember the OLM are calibrated for the type of oil the car calls for.
Meaning that my OLM is calibrated for Dexos (which is Semi Syn).
Other cars like say the Corvette- call for FULL Syn.... and those OLM are calibrated for its engine and Full syn oil.
2010 FWD LT1-Gold Mist Metallic- seats 8.
Build Date- July 31, 2009-2nd day of Spring Hill 2010 production.
2013 Equinox 3.6L - 88,000
2010 Traverse 3.6L- 153,000
2003 Trailblazer 4.2L- 181,500