Oh...he told me that it will work for more than 2 years...but I think u r right ..oversized rings may not work longer...compression is good..
One more point to be added
I was noticing him...when he was grinding the rings before installing it on pistons..this means the rings would b somewhat between the oversized and standard rings. Making hope of tight compact fit...as we observed that there was not any gap that time..the glass was very fine like New.