So far, the only response I have received from my ward’s constituent services director is an email from the DMV Director essentially saying that the bill I was given is correct, and there is no flexibility. He specified that the reading of the code is that a bill of sale is only used when a NADA value does not exist.

For additional context, the NADA value only tracks dealer sales, not private sales. Insane that private sales are taxed via an inherently unrepresentative guide, while not receiving any of the benefits of purchasing from a dealer (warrany, etc).