iPhone Upgrade Program

I currently have 1 month left in my 24 month upgrade program for the IPhone 12. I was going to upgrade through the program to the 14 pro but it would cost 50$ a month. It seems like I should just wait the month and then I can get a full trade in value for the 12 to put towards the 14 pro and lower my monthly payment. Am I missing something or does that sound right? Thanks I’m advance.