(a) In all cases where a person has been overtaxed or claims for any reason that taxes should be credited or refunded, the county governing authority may hear and determine such application to the extent of the interest of the county in the matter.

(b) In all cases where the county governing authority, pursuant to subsection (a) of this Code section, has authorized the tax collector or tax commissioner to credit or refund any overpayment of property tax in cases where the taxpayer has been overtaxed or has claimed that the tax should be credited or refunded, the authorization to the tax collector or tax commissioner shall be authority to credit or refund the proportionate amount of the state and county school tax represented in the overpayment and, in the case of refunds, he shall deduct such amounts from his next distribution to the state and county school boards, respectively.