The provisions of this chapter shall not apply to persons engaging in one or more businesses taxable under this chapter whose total gross income is less than $125.00 per month. Any person claiming exemption under this section may be required to file returns even though no tax may be due: If the total gross income for a taxable monthly period is $125.00 or more, no exemption or deductions from the gross operating revenue is allowed by this provision. (Ord. 1108 § 1, 1983; Ord. 814 § 4.2, 1976).