sourcing transaction line details in a customer search

I'm using a customer search to pull together data about purchase history. I've been able to get most of what I want, but I am stuck on one thing.

We are a software company (running SWE) and I need to be able to distinguish between concurrent and named seats in the search results. The only way I can see to do this is to look at the item name or description, as this apparently is not tracked separately.

So, I came up with a formula, which of course does not work so far. It looks like this:

case when {transaction.itemname} like '%Concurrent%' then {quantity} end