Question Confusing Everyone Regarding Perm

[support.gc]

What are the qualifications needed for EB2?

a) USCIS says we need advanced degree
b) Few Lawyers say we need advanced degree
c) Some postings on immigrationportal.com say people are getting PERM approvals under EB2 with a "BS + 5 years" experience.

Q) Does BS + 5 years experience considered as EB2 or do we require Master's Degree for EB2?

Q) How can these people who have filed for GC under Perm - EB3 having a BS + 5 years experience change from EB3 to EB2 after the application has been filed? in case they already had 5 + years experience before they joined the company. Is that possible?

Question for people who have become Guru's in immigration law after alot of suffering and surfing (Surfing = new worlds way of meditation).

 

[support.gc]

I think every one understands that it does not make much of difference if we are EB3 or EB2 when we are in labor certification stage. But it sure does make a difference when we are in I-140 and I-485 stage.

Considering BS + 5 Years experience is considered EB2. How and in which stage can one correct the error by changing from EB3 to EB2. Is that possible?

I have seen people have been asking same question in lot of other threads so I have made it new thread so everyone gets the idea of this issue at hand.