Regarding 10% ITC

I Think its not 10% ITC

its 20% ITC above ITC available in GSTR2A subject to ITC as per books 

So shall i go with 20% ITC formula?.. and when its 20% ITC then which date i consider My Final ITC on gstr 2...is it every month of 11 or after that

20% ITC rule is applicable from Oct 2019, you can claim unclaimed ITC in subsequent returns

@ sandip
u can view or download your GSTR2A at the time of filing your GSTR 3B.
if u file at 18th u can take the input available on 18th itself as per 2A

20% is being changed to 10% from the month of January 2020.

But what we have to understand here is that , such rule or norm though notified . 3b online Utility will not restrict you to 10 or 20 ITC as available from your 2A at that point of time .So your are still free to enter your self-assessed I.T.C in 3B.

I think the help desk team are aware of the recent amendments.This is the gap between G.S.T legislation and G.S.T  Technical wing that is GSTN, which is maintaining help desk. 

Although the 3B utility is not updated to restrict it upto 20% at present or 10% from Jan 2020 still the tax payers should calculate it manually and restrict himself to that extent. May be once the ITC restriction is settled from Jan 2020, they will update the utility. If tax payers do not restrict manually and the scrutiny comes then he will have to pay interest to that extent till the point of actual upload of the invoice by the supplier.