An employ was hurt on the job and has a Workers Comp claim. Said employ was salaried before the accident and switched to hourly after the accident because he is on light duty. His insurance was paid in full when salaried. He has been back to work

An employ was hurt on the job and has a Workers Comp claim. Said employ was salaried before the accident and switched to hourly after the accident because he is on light duty. His insurance was paid in full when salaried. He has been back to work for two months now and was notified last week that he no longer was going to have his insurance paid in full; only half would be paid. Is it legal for the company to retroactively charge for half of the insurance benefits back to the start of his change to hourly (2 months ago)?