Gst sale difference in gstr3b & gstr 1 & accounts

I am doing whole sales business from July to Feb I have filed GST return 3B & GSTR 1 Till date March 2018 NOt Filed While making abstract i have found a difference in GST Filing I have filed GSTR 3B Rs. 24950000/- Till feb and GSTR 1 is Rs. 28045000/- but what i filed in the GSTR 1 is correct and i have failed to show Rs.1645000/- in July Sales and Rs. 1575000/- in August Sales and i have not  claimed the purchase value till date of July & Aug can i show all the difference of Sale and  purchase amount in March 3B and in  March GSTR - I ( if ican show i want to take the difference amount in GSTR 3B or GSTR - 1 Filed ) I.e Total sales July to Feb Rs. 28 in GSTR- 3B is Rs. 24950000/- but in my abstract as per accounts i am having Rs.29256000/- and i have filed in GSTR -1 Rs. 28045000/-  Kindly do the needful