I too agree with your mechanic. And it’ll probably destroy your ozygen sensor as well.
The big problem is that most manufacurers today officially consider 1 quart every 1,000 miles to be acceptable. Check your owners’ manal and see of they reference an acceptable amount of oil usage.
Unfortunately, other than perhaps bringing the vehicle back to them every 1,000 miles and closely documenting the checks and the actual oil usage (using shopp orders would be a great way to do this), to follow up with the zone manager, there’s no way to directly “measure” oil usage.