You need to read clause 1.4. It grants the Engineer the authority to "add to, delete from, or otherwise modify, the requirements of this code".
Right or wrong, the Engineer has the responsibility and should something go wrong, both the Owner and the Engineer must answer for their actions or inaction.
If the Engineer allows the steel to be "prequalified" for his project, it is his prerogative.
I would submit the CMTRs for the steel and specifically request the Engineer's approval that the steel provided is "prequalified" that that one project. Bear in mind, there have been cases where the steel provided did not match the steel listed by the CMTR. I would recommend that a sample of one or two pieces of steel be tested for chemistry and the mechanical properties to verify the CMTRs are in fact for the steel provided. Frankly, I would not trust anything supplied by the Chinese until it has been independently verified.
Best regards - Al