Drawback deals with goods produced or manufactured from imported materials or excisable materials, as per Rule 3 of DBK Rules, 2017 and as per sub-rule (2) thereof (reproduced below), DBK is in respect of taxes suffered on the raw materials. On the other hand. Rule 43 of CGST Rules, 2017 deals with apportionment of ITC in respect of capital goods. Besides, Nonf.131/2016-Cus(NT) as amended by Nofn.cited by you clearly mentions non-permissibility of ITC only in respect of inputs and input services (12AA cited below). Accordingly in my view, both are mutually exclusive and hence there is no need to reverse the credit on CG in such cases. Please check whether the reversal of 80 already made by you covers inputs & input services in proportion to the export value. If so there is no issue.
(12A) The rates and caps of drawback specified in columns (4) and (5) of the said Schedule shall be applicable to export of a commodity or product if the exporter satisfies the following conditions, namely:-
Nofn.131/2016- 12AA(a) (i) the exporter shall declare, and if necessary, establish to the satisfaction of the Assistant Commissioner of Customs or Deputy Commissioner of Customs, as the case may be, that no input tax credit of the central goods and services tax or of the integrated goods and services tax has been and shall be availed on the export product or on any of the inputs or input services used in the manufacture of the export product, or
Rule 3(2) of DBK rules - In determining the amount or rate of drawback under this rule, the Central Government shall have regard to, -
(a) the average quantity or value of each class or description of the materials from which a particular class of goods is ordinarily produced or manufactured in India;
(b) the average quantity or value of the imported materials or excisable materials used for production or manufacture in India of a particular class of goods;
(c) the average amount of duties paid on imported materials or excisable materials used in the manufacture of semis, components and intermediate products which are used in the manufacture of goods;
(d) the average amount of duties paid on materials wasted in the process of manufacture and catalytic agents:
Provided that if any such waste or catalytic agent is re-used in any process of manufacture or is sold, the average amount of duties on the waste or catalytic agent re-used or sold shall also be deducted;
(e) the average amount of duties paid on imported materials or excisable materials used for containing or, packing the export goods;
(f) any other information which the Central Government may consider relevant or useful for the purpose.