The Commission may establish a pension or retirement plan for its employees. The Commission may: contract with an insurance company for a group, annuity, retirement, or pension plan; and contribute to the plan as the Commission considers equitable or as required by contract. The Commission’s contribution under paragraph (1)(ii) of this subsection shall be charged as expenses of the several functions of the Commission in the same proportion that the receipts of the respective functions bear to the total receipts of the Commission.