According to law it is evident that even with an approved EB-2 case, you have the option to file the I-140 under EB-3 – that's a choice open to you, and no one can dispute it. However, this doesn't mean that your I-140 and PERM are permanently tied to EB-3. What is typically done is filing the I-140 under the category that offers a more advantageous date. For instance, if you are in the EB-2 category and the EB-2 date is more favorable, you would file under EB-2. Conversely, if EB-3 is more beneficial, you would choose that option.
It's important to note that you cannot upgrade from an EB-3 PERM to an EB-2 I-140, but you can downgrade from an EB-2 I-140 to an EB-3 I-140 – or the other way around, downgrading from an EB-2 PERM to an EB-3 I-140.
So, when you have an EB-2 PERM, you have the flexibility to file under either EB-3, EB-2, or both. Importantly, this filing of the I-140 does not terminate your case or prevent you from returning to EB-2 in the future. Thus, there's no compelling reason not to consider filing under EB-3. As for whether it's better to file your case under EB-3 or EB-2, my recommendation would be to file I-140s for both categories – EB-3 I-140 and EB-2 I-140. However, for the I-485, it's advisable to file with EB-3 – that's likely the most suitable course of action.
I am thankful to Art who was my case manager in my green card application. He initiated my PERM process and help me out in each and every step till i got my physical green in hand. There were couple of bumps (RFE, etc) but the firm handled it so quickly and professionally without any issues whatsover. It is worth to mention about availability of Mr Khanna on coneference calls, as and when needed without any delay and whenever you have doubts or questions. I will also thank heather and others people and attorney that help me in getting my Green Card. Really nice law firm and highly recommended.