Best practice policies typically suggest that the people who are responsible for posting or verifying charges (such as coders) should not also be the same people who are responsible for accounts receivable (billers). It's standard accounting practice in many big groups or facilities, designed to avoid having your coding staff engage in coding practices that are done primarily to override edits and inflate reimbursement. There could be a potential that coders who are involved in accounts receivable might be asked to use that information to influence how they are expected to code, instead of coding based on regulatory guidelines.
The billing department is generally under the umbrella of the revenue people, with the coding department being under the Med Info umbrella. With different department managers and separate reporting structures, it can prevent the billing manager from influencing the coding staff to code based on payment alone.
That having been said, it's always a good experience for a coder to have the experience and understanding of how claims are adjudicated so that they can determine if coding (or billing) errors were made that impacted the bottom line. Overall, though, this is why certified coders are held to a particular ethical standard....if coders must be involved in accounts receivable (as they frequently are in small practice settings), they must set aside their billing hats when they are working as coders (and vice versa).
It's perfectly legal for coders to post payments, work denials, submit claims, collect copays and other revenue-cycle related work. What can be challenging (fraudulent, actually) is if they ignore or override correct coding initiatives and other coding regulations in order to get the claim paid.
