After doing my own research (no thanks to TT), I believe my scenario is outlined under the Instructions for For 8962 on page 18 under "Allocation Situation 4. Other situations where a policy is shared between two tax families" where the IRS says "Under the rules in this section, you and the other taxpayer may agree on any allocation of the policy amounts between the two of you. You may use the percentage you agreed on for every month for which this allocation rule applies, or you may agree on different percentages for different months. However, you must use the same allocation percentage for all policy amounts (enrollment premiums, applicable SLCSP premiums, and APTC) in a month."
I'm no CPA, but this seems like pretty straightforward direction that would be helpful for TT to at least have referenced somewhere. Since my adult daughter has enough earnings to make her "not a dependent" but not enough to support herself or pay any of the premiums, she is happy to have me claim 100%. Would have saved me several hours.
