L1B Blanket visa Max out time

I have reached US first time on 3-aug-19. My petition was approved on 15-feb-17. Now my I-94 and petition end date is 6-nov-19 and visa stamped till 13-Feb-22.
I have filled for petion extension.My question is after extension approved how long max can I stay in US?Is it maxm till my stamped Visa end date(next available 2years lapsing first 3years) or I can utilize maxm whole 5years(petition can be filled even after my stamped Visa end date)?
How does the the max out time gets calculated for L1B blanket?Is it from the start date of petition approved or is it from the start date of first port of entry date in US?


The max out time gets calculated based on how long you have actually stayed in US from the day you entered at US Port of Entry, not really on how long it was previously approved. You can work with your attorney and submit your dates of stay in US and submit such that you get maximum time for the petition.