Insurance companies must file rates with the state each year and have their rates approved. All but ONE company available in central PA immediately rewrote contract language to comply with Obamacare regs...that was years ago.
It would have cost the companies and therefore the insured more to maintain two seperate plan series. It was easier and cheaper to change the plans and be done.
Essentially...there are no remaining Grandfathered plans in the small group market. Some of the larger corporations may still have them though. The carriers are much more accomodating to a 2500 person group than a 25 person group.