You are correct in terms that DIT never have issued
declarations to DACA in CY11 and CY12.
Unfortunately, it has been found out that DACA had
applied GSP from the 2nd half of FY11. As US customs
basically look back the past 5 years, we have to calculate
the amended amount for the shipments inclusive of CY11 onward.
We sincerely apologize that it would cause you certain work
to be taken care of, but we really need your assistance for
the declarations for old DACA shipments.