Validity of Visa bulletin dates

[pnvmunindra]

My priority date is EB2-2010 Dec. As per October bulletin, my date is current. I will have to go to India and will be returning to USA on OCT 20. So, I will be applying I485 @ around OCT25. Say for instance, if the dates are retrogressed in Nov bulletin which will be released on Oct10, can I still apply based on October bulletin until end of OCT 31?

My question is: what is the validity of October bulletin (Recently released bulletin)?

Thank you for answering!!

[immihelp]

Validity of Oct visa bulletin is Oct 1 to Oct 31.