California Code, Revenue and Taxation Code - RTC § 41050

(a) The surcharges imposed by subparagraph (A) of paragraph (1) of subdivision (a) of Section 41020are imposed to each access line for which a service user has subscribed in any calendar month, whether or not the subscription covered all or part of any month.

(b) If a service user subscribes for service with one service supplier for a portion of a month and then subscribes for service with another service supplier for the remainder of the same month, the service user is liable for the surcharge to each of the access lines for which the service user has subscribed with the service supplier.