Unfortunately, Airtable is an extremely limited platform, so unlike other database platforms, you can’t sort by the values that are displayed in Airtable’s summary bar. Airtable gives us no programmatic access to those summary numbers at all, which can be extremely frustrating.
The only way to workaround this problem would be to create a completely different table where you just list your creative concepts — one record per creative concept.
After that, you would create a linked record field where you would manually link each concept to all of its related records from your PRISM table.
Then, you would create a rollup field to give you the average of the “cost per conversion” field for each concept.
Then, you would sort this table by the average cost (your rollup field).
(I would also email firstname.lastname@example.org to request that they give us programmatic access to the summary bar.)