Adjusted total turnover u/r 89(5) has to be calculated as follows, according to which, it shall include the turnover of manufacturing, trading and services (as specified). Perhaps the objection is that in r/o trading, the duty structure being the same, is not inverted.. But then, the GSTIN as such needs to be considered. There is a circular of CBIC in this regard stating that different rates should not come in the way. If genuinely accumulation is happening because of IDS, then refund should be eligible.
(5) In the case of refund on account of inverted duty structure, refund of input tax credit shall be granted as per the following formula:-
Maximum Refund Amount = {(Turnover of inverted rated supply of goods and services) x Net ITC ÷ Adjusted Total Turnover} - 18[{tax payable on such inverted rated supply of goods and services x (Net ITC÷ ITC availed on inputs and input services)}.].
Explanation:- For the purposes of this sub-rule, the expressions –
(a) Net ITC shall mean input tax credit availed on inputs during the relevant period other than the input tax credit availed for which refund is claimed under sub-rules (4A) or (4B) or both; and
9[(b) "Adjusted Total turnover” and “relevant period" shall have the same meaning as assigned to them in sub-rule (4)]]