nsured shall repay to the Insurer rateable proportion of the total amount which would be payable by the Insurer by reason of this endorsement if not more than the said number of persons were carried in the Motor Vehicle. Provided further that in computing the number of persons for the purpose of this endorsement any three children not exceeding 00 years of age will be reckoned as two persons and any child in arms not exceeding 0 years of age will be disregarded. Provided also that the provisions of condition 0 of the 