Adding Item Age to Sell-Through Report

lizatesby

I'm looking to add item age to a sell-through report, so that I can view not only the sell through rate but also how long of a selling time each line of the desired grouping of items (without creating a second report.)

Does anyone know how to perhaps add a custom measure for this?

The report has a Last Received Date, that I expect could be manipulated into finding the number of days since then, but I'm more interested in the First Received Dates.

Thanks!