How do workers accrue leave under the City of San Diego Paid Sick Leave Ordinance?

Q:  “Regarding the City of San Diego Paid Sick Leave Ordinance: Our existing policy is that all employees, full-time and part-time, earn two hours per pay period, and we are on a semimonthly pay period. Over a year, the total is 48 hours. To my understanding, in the city of San Diego, employees earn one hour per 30 hours of work, or they earn hours through an up-front method of 40 hours at the beginning of each benefit year. Does our existing policy satisfy the requirements?” —Cecilia, California