When a loan is made under this Act to the members of a village-community or to any other persons on such terms that all of them are jointly and severally bound to the Government for the payment of the whole amount payable in respect thereof, and a statement showing the portion of that amount which as among themselves each is bound to contribute is entered upon the order granting the loan and is signed by each of them and by the officer making the order, that statement shall be conclusive evidence of the portion of that amount which as among themselves each of those persons is bound to contribute.