I think govt not enabled such a facility in form GSTR 3B , Hence we need to pay without adjustment of previous credits for July and august when ever u filed the TRAN 1 then only it will be adjustable in GST while filing GSTR 1 for September month.
Vice President of GST Network Shri Shashi Bhushan Singh conducted a webinar to clarify certain issues related to filing of GSTR-3B GST as under:
(1) Transitional Input Tax Credit of Excise, Service Tax, VAT etc. cannot be claimed in GSTR-3B. He said that "The legal provisions don’t allow claiming transitional credit through Form GSTR-3B, they have to claim through Transition Forms". (Yesterday's viewpoint was only the viewpoint of Ask GOI)
(2) He further explained that any revision in GSTR-3B must be routed through Forms GSTR-1, GSTR-2 and GSTR-3.
(3) Refund (if allowable as per section 54 of CGST Act, 2017) CANNOT be claimed under Form GSTR-3B, excess ITC can be carried forward to subsequent months for setting off liability.
(4) Where there are no inward or outward supplies during July & August, ‘Nil’ return must be filed.
(5) Composition scheme dealers shall file Form GSTR-4 in the month of October, while e-commerce operators supplying own goods & services will require to file Form GSTR-3B, but in other cases, they will deduct TCS and file Form GSTR-8 which is yet to be notified .