Let me start by saying I am no expert on this.....
Are you sure they are not looking at the "EGR Readiness code" not being set?
I too am in Mass and just reverted to Stock for the inspection. When running Spartan
210 both the catalytic and EGR readiness codes were not set. Once I went back to stock, the EGR showed ready but the catalytic continued to show not ready (caused by no downstream O2 sensor?). Upon looking at the passing inspection report under emissions, it showed EGR passed, and Catalytic unavailable.
If they are looking at the EGR readiness (not pass or fail just not ready) as a criteria for ready to test, would they say to drive it more?
Also, I have been wondering if somone was running Spartan
150 or lower where the EGR is enabled would it show EGR ready. I plan on doing this test after I do the delete again so next year at inspection time I will know.