Limitation as to Classes of Loans

No association shall make any loan other than an amortized loan unless at least ninety per cent of the unpaid principal of all its loans then in force be amortized loans as defined in Section 130109 of this act, and no association shall make any loan other than an amortized loan payable in monthly installments unless at least eighty per cent of the unpaid principal of all its loans then in force shall be amortized loans, the note or obligation for which provides for installments of principal to be paid monthly thereon. No association shall make any loan upon the security of unimproved real property if the unpaid principal of all its loans then in force on unimproved real property exceeds three percent of the unpaid principal of all its loans of all classes then in force. The limitations of this Section 130115 shall not apply to loans made pursuant to Section 130101 of this act.