You're confusing items....I quote all-inclusive.... I, however, need to know at the end of the year how much I've collected for those expenses vs how much I've spent,
One has no bearing on the other. I have detailed accounting of my costs across all departments and activities, even at the single event level. It does not mean that I need to itemize the bill on the client side and I don't.
If I were to itemize a cost for the sound system, then most U.S. states deem that portion of the invoice to be a rental and require sales tax. I don't do that, because at no time does the equipment leave my own custody and care - and that eliminates an unnecessary cost to both the client and myself. If a carpenter lists an amount for his tools - then he too would have to charge sales tax on that amount.
At best, I will break out the fee for discreet service categories, such as lighting, audio/video, graphics, etc. which helps people understand how their event cost changes as their needs change or grow. I do not however, have numbers that apply to 12 versus 24 up lights, etc. because again - that defines a rental not a service or production. No one is told how many up lights I bring to an event. There is a result that needs to be achieved and that is what they pay for - not the pieces used or unused to attain it.
If I am doing a rental and then riding along as a technician - then by all means I would itemize. That's just not the case with DJ gigs and much of what I do.