Taxpayer's unreimbursed medical expenses exceed the 7.5% threshold
Taxpayer sees doctor in December and in compliance with doctor's wishes pays for procedure at time of service and then submits bill to insurer.
Insurer dithers (and questions claim etc.) but finally pays claim in late April (after taxpayer filed 1040).
Does this force a 1040X or can it be considered a negative expense in following year. (taxpayer will be over the threshold in following year.