Reimbursement for add-on codes

I am looking for rationale on why it would not be appropriate to apply multiple surgery guidelines with regards to an add-on code. Any references that anyone could give me would be greatly appreciated.

add-on codes

Modifier 51 establishes pricing
t is not appropriate because an "add-on" code is initially valued as a secondary procedure. If you apply modifier 51 (which is inappropriate) then a payor may apply the multiple procedure reduction, which is also inappropriate. Look at the symbol beside the add-on codes in the CPT manual. The plus (+) symbol, which designates add-on codes. Add-on codes are used to denote a code that is closely related to a previous code in the same section and may be identified by specific language in the code description, such as "each additional" or "(List separately in addition to primary procedure)." The most important things to remember about add-on codes is that they are always performed in addition to the primary procedure and may not be reported alone or without the parent code they relate to.

add on code

Medicaid is applying the mulitple surgery guidelines to an add on code. The add on code 64476 was billed in conjunction with 64475. I am looking for written rationale for them as to why it is not appropriate to do this.