In making such adjustment and apportionment of property, indebtedness, and rental obligations to an approved school building authority, the amount and assessed value of land acquired by or taken from such districts, as compared with the amount and assessed value of the other land in the districts, as well as the value of the school grounds, together with the buildings thereon, and the furniture and equipment therein, and other school property in such districts, shall be taken into consideration in determining the amount, if any, that shall be paid by one district to another, or in apportioning the indebtedness, and rental obligations to an approved school building authority, if any, that shall be assumed and paid by any of the districts. Such adjustment and apportionment of property and liability shall be made by the boards of school directors of the several districts concerned, before or during the first school year after such boundaries have been changed.