Your mechanic is exaggerating. Sure, Honda wants to sell you a new car in the future, but they have built up a solid reputation for reliability and long lived cars. Their oil change monitor system isn’t going to be designed to ruin your car’s engine. I have a 2006 Honda Accord, and I’m following the service monitor system for oil changes and maintenance. I expect it will last for several hundred thousand miles without a problem.
With all that said, changing the oil early won’t really hurt anything and if it makes you feel better it’s really cheap peace of mind.
Our new GM car is headed to a predicted 12,000 miles at oil change time according to the computer. If Honda and GM agree, there must be some validity to the computer program. There you have it from two different sources.
For those who don’t trust the computer, what you are saying is that you don’t trust the people who designed and tested your engine who also developed the oil change monitor program.
Our owner’s manual says to change the oil per the monitor and also at least once per year.
For those who don’t trust the computer, know that when cars first became available there were people who were against them; wanted to keep their horse and buggy. You might be related but likely not to the horse or its behind.