The director of services for the blind may, at the director’s discretion, decline to purchase material and supplies for any blind person under this part, whenever and if information available to such director indicates that there is a probability that the amount of such purchase will not be repaid to the state, that the blind person in question possesses sufficient financial ability to purchase such raw materials, that through intermingling of goods the raw materials and supplies purchased with advances from this fund or the finished product may not be satisfactorily identified to such an extent that a contract repayment may be enforced by identifying the finished product.