Originally Posted by bgriff

Taxes will be charged in 2 separate transactions -- Delta always charges each person/ticket separately.

Award ticket taxes are not officially reimburseable under the credit, though people have had luck with them being reimbursed automatically anyway. But there's a chance they don't go through for you, especially with the amount of each transaction being relatively high at ~$140. But if you're going to buy the ticket anyway, it's worth a try.