GSTR-3B AUTO POPULATED ITC

Auto populated 3B take whatever filed in the concerned period till 11th of that perticular period like if dealer files it's R1 of sep in Nov it shows in 2B and same will be auto populated in Nov month 3B what if the other party already claimed in sep returns and also if the seller file R1 after 12th of previous month it also taken in current month returns so this creates lots of confusion regarding itc available to claim as some Dealers file R1 quarterly

Good Evening. Our company's actual ITC is 3 Lakh. But, in 2A its about 1.5 Lakh only. Pls refer my points and assist me accordingly;
Nov Actual ITC 3.0 Lakh as per Accounts book.
In 2A ; 2.0 Lakh ( It includes prior month ITC too, supplier returns quarterly or delayed.)
in 2B ; 1.5 Lakh.
I am not able to edit and put correct figures in 3B. Also, differences in RCM too.