Under Medicare facility payment methodology, facilities are reimbursed a case rate for these types of injections. Add-on codes, such as the additional levels for these procedure, are 'packaged', which means there is no separate payment amount assigned to the add-on codes, and the reimbursement is included in the case rate paid for the base code. This is often misinterpreted to mean that Medicare 'does not pay' for these codes, but that is incorrect. Since the Medicare facility reimbursement is a prospective payment system, the case rates are calculated to be an average payment over a group of similar types of procedures. It does not mean that these codes are denied, or that they should not be billed since they do not get a separate line-item payment - it only means that the payment assigned to the claim is already calculated to include, on average, the extra reimbursement for those additional procedures when they occur. So you definitely should bill for those additional levels, even if they don't change the total payment of the individual claim, because you want to accurately reflect the services being performed so that those case rate payments will be accurately calculated.
Of course, for payers that do not follow CMS reimbursement methodology, the reimbursements and billing rules may vary, and will depend on the payer policies and/or the terms of the facility's contract.