"Insurance With Other Insurers: If there is other valid coverage, not with this insurer, providing benefits for the same loss on other than an expense incurred basis and of which this insurer has not been given written notice before the occurrence or commencement of loss, the only liability for the benefits under this policy shall be for the proportion of the indemnities otherwise provided hereunder for the loss that the like indemnities of which the insurer has notice (including the indemnities under this policy) bear to the total amount of all like indemnities for the loss, and for the return of the portion of the premium paid which exceeds the pro rata portion for the indemnities thus determined."
AS 21.51.210