Notwithstanding the provisions of § 34-13-50 the obligations of any person in the form of notes or drafts secured by shipping documents, warehouse receipts or other such documents transferring or securing title covering readily marketable nonperishable staples when such property is fully covered by insurance, if it is customary to insure such staples, shall be subject:

(1) To a limitation of twenty-five per cent of such capital and surplus when the market value of such staples securing such obligations is not at any time less than one hundred and fifteen per cent of the face amount of such obligations;

(2) To a limitation of thirty per cent of such capital and surplus when the market value of such staples securing such obligations is not at any time less than one hundred and twenty per cent of the face amount of such obligations; and

(3) To a limitation in addition to such thirty per cent of such capital and surplus increased by an additional five per cent thereof for each and every additional five per centum of the market value of such staples securing such obligations not in excess, however, of a total limitation of fifty per cent of such capital and surplus.

But this exception shall not apply to obligations of any one person arising from the same transaction or secured upon the identical staples for more than ten months.