For any continuous cable service interruption or loss of service in excess of 24 hours, the grantee shall make a pro-rated refund of such subscriber’s regular monthly charge to each subscriber so affected, upon written request of a refund from such subscriber. The 24-hour period shall commence when the grantee learns of such outage whether through subscriber notification or notification by the grantee’s maintenance personnel. Such refunds shall be pro-rated by multiplying the applicable monthly service rate by a fraction whose numerator equals the number of days of the outage and whose denominator equals the number of days in the month of the outage. For purposes of this subsection, an outage shall be defined as a subscriber’s receipt of less than two-thirds of the authorized basic cable service channels, or loss of any premium channel. The grantee shall not be required to grant a refund in the event that an outage is caused by any subscriber.