I'm trying to make a template file to use for starting individual jobs; this file will be pack-n-go'd into a folder for each job.  I want the BOM in PDM to show the number of stock parts needed to build the components of varying sizes.

In the picture, the grey parts are standard size, so they're easy.  The blue parts are what I call Filler W and Filler L, because they fill the gap left when the standard parts are put in.  Say the overall rectangle is 85" x 83", the corners are 6" and the standard straight part is 30", Filler W winds up being 13" and Filler L is 11".  This is all fairly simple algebra, and I can make this appear in the model and the BOM with no problem.

The part I am stuck on is showing the number of stock parts needed to make the 2 13" and 2 11" parts.  As the overall size of the rectangle changes, this number could be 1 to 4.  I can write nested if statements in excel to work it out, but how can I get that info into PDM for the BOM?

My main assembly has several sub assemblies that work essentially this same way.