As a contractor, I would just charge you for the time it takes to itemize an invoice while I do it sitting on a call for another job I’m also billing for. And I would be very thorough with my itemization so you know exactly what you’re getting…
The non-itemized invoice is free. We can argue over contract terms if you want to or come to an arrangement if you don’t feel you got your money’s worth, but if I disagree the result is going to be completion of the terms of the contract and we go our separate ways. I’m not hurting for work, I can fire an obnoxious customer if it buys me QoL.
The pandemic tipped the balance of power from the money men to the workers. We’re going to watch this dynamic play out in ways large and small, but the net is that employees have a lot more power to set the terms of engagement than employers do right now.