Oversight of Medicare Billing Code Cost Act This bill requires the Office of the Inspector General of the Department of Health and Human Services to report on the processes for adding, modifying, and removing billing codes under Medicare. The report must include recommendations for administrative and legislative changes that may improve the transparency and oversight of these processes. In addition, the Centers for Medicare & Medicaid Services must annually publish on its website a list of billing codes that were added under Medicare during the previous year, as well as the associated volume and expenditures for such codes.