Not a very helpful answer. However, I have figured out a workaround for a piece of software that is clearly poorly programmed and not functioning correctly in this area.
Quicktax optimizer was selecting myself (the primary left-hand taxpayer) to claim the medical costs, but I had changed this on the medical expense worksheet (or the optimizer?) to my spouse (taxwise, there is no difference). As above, the optimizer was blocked from selecting the correct 12 month period. If I then changed the dates on my spouse's (secondary, right-hand taxpayer) medical expense worksheet (the intuitive form to adjust because it had been selected), then the problem persisted. If however, I go to my (the primary left-hand tax-payer) medical expenses worksheet and manually change the dates, then the dates remain selected and the total now adds up correctly to the full total, then I can switch to my spouse claiming the expenses.
The issue is solved for me since I know the exact twelve-month period that I want to use and do not need to run the optimizer. I leave it up to TurboTax to troubleshoot further to understand if there is a fault in the optimizer, or if it was changing the claimant that blocked things from working.
