It is not a tax payment. As Critter said in her latest post, she was mistaken when she said that the amount you have to pay back is on line 70 of Schedule 5. The amount you have to pay back appears as a tax on Schedule 2 line 46.
If you were entitled to a higher premium tax credit than what you received in advance during the year, the additional credit would be on Schedule 5 line 70. But that is not your situation. You either get an additional credit on Schedule 5 line 70, or you have to pay back part or all of the credit on Schedule 2 line 46. There would never be entries on both of those lines. In your case, the amount you have to pay back is on Schedule 2 line 46, and Schedule 5 line 70 is blank.
This will be clear to you if you look carefully at Form 8962 lines 24 through 29.
