No reaction for both, it's fair, both are PAM. 13 level so we use 1 x 4th Level slot on first strike that hit, level 3 slots after that and then 2 level slots. Let's do 2 full rounds comparsion.
First turn: Attack, attack, Attack, bonus attack = Smite 1 x 4th Level, then 2x Smites 3rd level...