No. You may earn Promo Code Cashback from the initial FavePay Later transaction (depending on promo code terms & conditions). However, this reward cannot be used to offset any upcoming installments. The second and third FavePay Later installments will be paid fully using your primary card under your FavePay Later.
The earned Promo Code Cashback can be used for a different purchase/transaction. Fave Cashback can be used platform-wide, while Fave e-Cashback can be used for Fave Deal and eCard purchases. Find out more about cashback from our Cashback section HERE.