We having been working a lot recently with Allowance Tables and they can be confusing. Allowance tables show you what you are allowed to charge. When you post a charge, it should show your usual fee (usually fee schedule 0) and then show a Transaction Writeoff for the amount discounted. The Bluebook, however, shows what the insurance company will pay which could be a percentage of the allowed fee or a flat fee depending on the insurance. If computer is estimating a $0 payment, it is probably a Bluebook issue unless the Allowance Table shows $0 as the allowed fee.