Reason being, if you pick over 2h at 38, that sets a game total of 65. If it falls between 73 and 65, cha-ching for you. If it stays under 65, you push (assuming same odds and amount). If it goes over 73, you push (assuming same odds and amount).
If you instead pick the under 38 for 2nd half, you could lose both if the score is greater than 73 . You could also win both if the score stays under 65.
Your call.