There can be such a thing as "too much information."
I recently got hired to hang a chandelier. The reason? In this new house, the owner will not allow the original sparky to return.... seems the owner found that the fixture the sparky was charging him $2100 for was readily available for $800.
Are there costs involved in obtaining, transporting, storing, and maintaining materials? Absolutely. Yet, it's hard for the customer to not have hurt feeling when it looks like, from the invoice, you're planning to retire on the sale!
My own model is based upon minimal mark-up, and a seemingly high hourly rate. Sometimes, one of my customers will hire "the other guy,".... and learns that the imagined savings never appear. This, of course, makes for a loyal customer.
Another contractor uses a form, where the customers' invoice doubles as a worksheet for all his charges. This often results in the customer questioning every line. Personally, I consider time spent debating / explaining the invoice to be wasted time, and would rather eep things simple.
