GST related query

There is amendment coloumn in gstr 2A for
Amended b2b, amended tcs/tds, amended credit/debit note,
1.Based on this we need to reverse / claim itc?
2.for 105% itc calaculation we need to consider above mentioned amendment?
3.105% is calculated on GSTR 2A or GSTR 2B?
4.if previous month invoice amended it is autopopulated in that month GSTR 2A, we need to consider this amendment in current month 105% itc calculation? if yes what amount of amendment value full value or differential value?