Why is there no Listing SKU field for Program Listings?

Community Explorer

I'm very new to Canvas Catalog, and we're about to release our first paid program.  The program comprises 2 courses. Each of the courses has a Listing SKU, but the Program Listing does not have a Listing SKU field available. Is this for a reason, and if so, can someone explain why it is not a good idea to have a Listing SKU for a Program Listing?

Since we've not yet seen a Program purchase, I can't tell whether the SKUs for the 2 courses of the Program will be shown in the payment gateway audit trail or not. The SKU ordinarily shows up in the payment gateway audit trail as "Item Description" when an individual course is purchased. 

Thank you for your time reading this.