registration under SEZ and DTA of same entitit

we have got registration under GST of SEZ branch and also mentioned additional place of business of DTA branch in that but later we someone clarified that we have to take separate registration for DTA then we applied as altogether new registration but GSTN says that since TIN have already been used hence it can not be done..Please suggest...can one PAN entity have two branches one in SEZ and one in DTA in same state, have two registration...under VAT regime it was carrying same VAT number while doing transaction between both branch.