I mentioned this before in another thread a while back, but I'll mention it again here. It doesn't quite come out the same in the wash when you overpay SALT and get a refund the following year versus getting the refund in the same year. Getting the refund in a later year could end up costing you some extra money in taxes because the refund counts as income, not as a negative offset to deductible taxes paid in Schedule A.
A few years ago, I received a state property tax rebate in the same year I paid the property taxes. Originally, in my skeleton income tax spreadsheet, I had combined this check with another state property tax rebate I received for the previous year's property taxes in Line 10 of Form 1040. But as I was reviewing this at tax time, I realized that the same-year rebate belonged in Schedule A as a reduction in SALT paid. When I made the adjustment, my income taxes dropped for 2 reasons. The first, the largest part, was an increase in my ACA subsidy which is based in part on MAGI. MAGI includes SALT rebates shown as income, not as reductions to Schedule A taxes. The other was a small increase in deductible medical expenses because I was now taking 10% of a slightly smaller AGI to subtract from my actual expenses, leaving me more to deduct.
This effect I also had to take into account when I was figuring out whether or not to "bunch" my deductions over a 2-year period. If I took the SD, I wouldn't have to add back any property tax rebate in the alternating year and would therefore not reduce my ACA subsidy or med expense deduction, either.