"If the ex-wife is agreeable to it, you really want to allocate 100% to the ex-wife."

On the original topic, we are told 1095A Premium is $1908 and Advanced Payment is $1585. The difference is $323, or similar to the $332 that the ex-wife paid all year (perhaps with a typo = transposition error)?

And you stated: "Both the man and his ex wife are the recipient of the 1095A"

So why wouldn't you put this on the Ex-wife?