There is a loose relationship between ductility and toughness. There is also a relationship between hardness, strength, and ductility. Then there is the specification; it rules. If the material in question does not meet the criteria provided by the specification, it simply doesn't comply. There are often rules included where if a test results falls outside the published limits, a new test can be performed. I suggest an additional test be performed if it is permitted by the material specification cited by the customer. However, I know of no magic wand that allows the vendor to over ride the requirement of the specification.
Steels used for the construction of bridges often include maximum values for the mechanical properties to ensure they perform in service in a predictable manner. The end used that included the material specification in the design, purchase order, or other contract document does not bear a responsibility to the vendor to justify the requirement. The vendor does have a responsibility to proved the materials as specified by the customer.
Best regards - Al