There is another side to this.  When I worked in the office machine business we had a charge for shop supplies (I forget the exact term used).  The reason was the company was audited by the State of Indiana for sales tax and an auditor chewed on them because they were using supplies in the shop and bit paying sales tax on them when purchased or "sold".  In this case they were sold internally and used in house. I asked why it couldn't just be incorporated into the shop charge like the lights and water.  The response was because the tax folks had to see a separate item with sales tax charged on that item.

Yeah, it is nit-picking.  That's part of a tax auditor's job description.

Friend of mine is Illinois based but does quite a bit of business in Indiana.  Few years ago the State of Indiana audited him for sales tax.  Got all done, everything came out perfect, auditor said "By the way, let me see your Indiana income tax forms."

He replied "Indiana?  We are based in Illinois."

Auditor responded "Doesn't matter.  You do work in Indiana, you have to pay income tax on it"

They collected back taxes for 3 years, said they could have gone back 25 since the company "obviously" was trying to avoid them.  It was particularly irritating because over it's 25 year history the company had 3 different accountants, one based in Indiana, one a "biggie" with Indiana offices, and NONE had ever said a thing about filing Indiana income taxes.

So getting back to the charge for consumables tacked on to a shop bill ... get used to it.  Tax folks are going to force it on the companies.