The unit is a kept appointment, and the platform cannot see one
Between a click and a sales conversation sit two conversions that most accounts never measure, and both of them leak.
A form submission becomes an appointment only if somebody reaches the person and books it. An appointment becomes a sales conversation only if it is kept, with the right people there. Each of those steps loses a share, and the share is not small.
Optimizing on form fills therefore optimizes for the wrong thing. Campaigns that produce plentiful cheap inquiries can produce very few kept appointments, and the account will report them as the better performers for as long as nobody feeds back what happened.
The fix is to send the real outcome back into the account rather than to admire the top of the funnel. Whether the appointment was set, and whether it was kept, are the two facts that make bidding meaningful.
That requires the office and the account to be connected, which is usually the actual project. Most dealers have this information somewhere and it never travels to the people spending the money.
Once it does, the reporting frequently reverses. The expensive campaign producing few but serious inquiries turns out to be the one paying for itself.