gstr4 annual return mistake f.y.19-20 adjustment next year 20-21

A gst registered composite scheme dealer annual return gstr4 in f.y.19-20 filed. dealer mistake sale turnover Rs:35 lacs and tax pay Rs:35,000/- show in cmp-08 return but not reporting table 6 tax rate wise(outward supplies) in f.y.19-20 gstr4 .

Question:

Dealer gstr4 19-20 year mistake turnover next year f.y. 20-21 (two years sales turnover reported) adjustement set off tax previsous negative liability tax allowed in gst act.