I agree - which appears to conflict with this statement from the VZW rep above:

"vzw_customer_support Sep 16, 2015 8:21 AM (in response to lmwsport7)

lmwsport7, upgrading to a new phone is an exciting time. I understand wanting to get a definitive answer to the appraisal value of your iPhone 5s. Having the option to trade in your device towards a credit is a great one. The value is not tied to your account payment method or plan. At times the appraisal value can change due to promotions we are running or any agreements we have with Apple. The values are subject to change at any time."