Hi Mike,
Maybe the better wording for the Trade-up page would be the following:
“If you are trading in multiple items the current value of what you are trading-in must equal or exceed the current value of what you are purchasing in order to qualify as a Trade-up.”
We could program this automatically into our backend but that would mean having to pick what you are trading in from a huge list of products. This may be more cumbersome than just the statement above of what a Trade-up means mathematically. What do you think?