Executive office space rentals in San Diego on average cost between $5-8 per square foot. According to the SquareFoot Calculator, the average estimated budget for a 200 sq. ft  executive office space rental in San Diego, is around $1,250 per month.
Executive office spaces (fully serviced) typically include the following amenities:
Utilities
Furniture
High-speed internet
Receptionist
Secretarial support
Phone services
Parking
Therefore, a fully serviced office per sq. ft. rent price is completely different from a large commercial space rental that does not have any amenities.