I also think it’s showing extreme naïveté when it comes to the fallacies of “myths programmers have about X” where X in this case is billing. Billing and money is hard not because of the technical aspects of moving 1s and 0s correctly but because it’s a socially mediated system with a lot of messy things that tend to require humans.
I think you've succinctly illustrated why software estimation is notoriously unreliable.
Those estimating do not yet understand the problem.