Delayed Payment of SGST/CGST on RCM Basis

Tax advocate raised bill to P. Ltd. Company in FY 18-19; payment made by cheque on 31.3.2019; March'19 GST return filed without including RCM payment of SGST & CGST; Balance Sheet finalized (without showing liability of RCM) and ITR filed.

Question - Can we make RCM payment of SGST/CGST with Aug'19 GST return now, and take credit for RCM payment in Aug'19 return itself? One advice was that RCM payment has to be done only in Annual Return for FY 18-19. Our concern was that end-Sep'19 is the last date for claiming ITC for FY 18-19. Experts please advise.