An earned premium must be charged for the insurance bound by covering notes. Such earned premium shall not be unfairly discriminatory, but shall be consistent with the premium rates usually used by the insurer for risks of the nature of that bound by the covering note. When the policy issued pursuant to Section 2274.3 covers not only the period of time included in all of the covering notes but extends beyond the termination of the last one thereof, then the earned premium may be included in the premium charged under the policy and need not be charged separately therefrom.
Cal. Code Regs. Tit. 10, § 2274.4