The following provisions shall apply to Board of License Commissioners inspectors for the official use of their automobile: Each full-time inspector shall be entitled to ten cents ($.10) a mile for each mile that they use their own automobile in their official duties up to a maximum of Two Thousand Four Hundred Dollars ($2,400.00) during the fiscal year. Each part-time inspector shall be entitled to ten cents ($.10) a mile for each mile that they use their own automobile in their official duties up to a maximum of One Thousand Two Hundred Dollars ($1,200.00) during the fiscal year. Payments shall be made monthly on vouchers submitted by the Chief Inspector and approved by the Chairman of the Board of License Commissioners.