Section 6622 - Refunds from surplus; assessment corporations(a) Subject to the requirements of this article for the accumulation and maintenance of minimum surplus, the surplus of any assessment corporation shall be eligible for equitable distribution to its members, but no distribution shall be made until authorized by the corporation's board of directors nor until approved by the superintendent.(b) In authorizing any such distribution the board of directors of an assessment corporation may provide for apportionment thereof among separate groups of members on the basis of underwriting experience equitably classified according to major kinds of insurance.