Similar style construction business I believe but not flooring. We don't sell the "flooring" to the customer box by box per say.

We sell 3000 sq. ft. installed for a fixed dollar amount and have labor and material costs and don't show itemized bills to customer.

The only way I have figured out how to do this using inventory adjustments by adjusting qty on hand.

So I cut a PO to my vendor for say 20,000 sq. ft of flooring. We receive it and it shows up in my inventory.

Then on each job I adjust "qty on hand" and select the job I'm moving the inventory to. It works but becomes a little cumbersome.

Looking at Quickbooks online and I think you can do the same but you create a sales order with inventory items and basically sell them to the custom behind the scenes internally for zero dollar amount. Only way to get the costs showing on each job.