Any notice which is by this Act required to be sent to any policy holder may be addressed and sent to the person to whom notices respecting such policy are usually sent, and any notice so addressed and sent shall be deemed and taken to be notice to the holder of such policy:
Provided that where any person claiming to be interested in a policy has given to the company notice in writing of his interest, any notice which is by this Act required to be sent to policy holders shall also be sent to such person at the address specified by him in his notice.