iPhone 15 Preorder Thread

Hola,

This is our first time trying to do an upgrade with a trade-in since switching to T-Mobile a year ago.

Según https://www.t-mobile.com/news/devices/t-mobile-to-offer-all-new-iphone-15-lineup:

T-Mobile for Business customers can get iPhone 15 Pro on Us (or up to $1000 off any iPhone 15 model) with 24 monthly bill credits plus tax when trading in an eligible device on Go5G Business Plus o Go5G Business Next and eligible Business Unlimited plans. Or iPhone 15 on Us when switching to T-Mobile with 24 monthly bill credits plus tax on an eligible Business Unlimited plan — no trade required. 

However, I went to the store today, and was told that the max trade-in value on the Business Unlimited plan is $650.

Is it a better bet to call customer service to verify the trade-in value and do the upgrade over the phone?  Are there any additional fees when upgrading over the phone?  Our business rep had suggested that we go to a store since that's the best/easiest way to process a trade-in upgrade.

¡Gracias!