Improving Oversight and Accountability in Medicaid Non-DSH Supplemental Payments Act This bill amends title XIX (Medicaid) of the Social Security Act to direct the Centers for Medicare & Medicaid Services to: (1) issue guidance to states that identifies permissible methods for calculating certain supplemental payments, excluding disproportionate-share payments, made by state Medicaid programs to providers; and (2) establish annual reporting and auditing requirements for states making such supplemental payments. Federal payment with respect to such supplemental payments shall be conditioned upon a state's compliance with these reporting and auditing requirements.