The premium tax credit is a fixed amount based on the taxpayer's income and the standard cost for a policy, right?  So if they paid more or less than that standard rate, it shouldn't make any difference.  

If they itemized and had enough medical expenses to claim, the rebate is like a state tax refund, and should be added back to income in the year received to the extent there was a tax benefit from it.  Except in backwards states like Arizona, where 100% of medical costs are deductible without a 7.5% limit, if you don't have to add back your state tax refund on the state return (yes, state income taxes are deductible, remember, it's Arizona) then you shouldn't have to add back your excess medical either.