A savings bank may invest the funds mentioned in ORS § 716.410 in notes or bonds secured by a mortgage, deed of trust or similar instrument to finance the construction of buildings and improvements appurtenant thereto, if before making the investment, the savings bank requires sufficient guarantee from the contractor, builder or owner for the completion of the construction in accordance with the plans and specifications and within the estimated contract price for the construction. Moneys shall be advanced from time to time during the progress of construction upon a certificate of estimate to be furnished by the architect, contractor, builder or superintendent in charge of construction or the owner. [1973 c.797 § 371d; 1977 c.135 § 37; 1985 c.554 § 8]