Question on Promo

I ported my number over from Verizon onto a Go5g Plus plan and received a free iPhone 14 Plus using promo ID230143. I still have an unlocked 14 pro max from before and was wondering if I switched back to that phone if I would still continue getting a monthly credit for the 14 plus. Or do I need to keep the promo phone associated with the line to continue getting the monthly credit?