I figured it out, although there is still a $1 discrepancy. I can live with that.
There were three issues, one an accounting error on my part, the second an extra credit card fee that the insurance company was charging me for paying my bill by credit card (a fee that I cannot include in my premium paid), and the third a premium tax credit.
I reported in my initial post that my total annual premium paid was $3,946. I made a mistake in one of the monthly premiums that I was tracking. My premium assistance was reduced in April, 2022, due to the updated AGI from my tax return. I had mistakenly moved that reduction to March, 2022, meaning that my figure for March was incorrect, over by $133. Adjusting that reduced my annual premium paid to $3,813.
The second issue was a monthly $2.92 credit fee, an annual total of $35.04. Removing that left me with an annual actual premium paid of $3,778.
Finally, when calculating the premium tax credit, the figure was $598.00, essentially a refund of premiums paid. I can't include that in my annual actual premium paid figure, so removing that leaves me with an annual actual premium paid of $3,180, rounded to the nearest dollar.
The figure that TT used in the Medical Expenses Worksheet was $3,179, a difference of $1. I don't know where that $1 came from, but I'm okay with not knowing that. I think (I hope) I finally understand how this works.
