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 just got my H-1B renewed for a 7th Year through the Law offices of Rajiv S. Khanna. Rajiv, with whom, I had been corresponding on various issues pertaining to my greencard, H-1B, etc., is always accessible and extremely helpful. He is extremely prompt in responding to the email--usually in a few hours and sometimes almost instantaneous. His promptness had always helped to ease the anxiety levels. I will be always be grateful for that, THANK YOU RAJIV. I also would like to thank Richa Narang, Shivane Sharma for their work and time on my GC case. And, Anna Baker and Charu Bhagat for their time and work on my H-1B 7th Year extension. I had countless conversations with Richa, Shivane, and Anna. They are not only diligent and professional in the work they do, but more importantly all the three have a great human trait: EMPATHY. They are prompt in responding to emails and in keeping me informed of the status. My sincere thanks to all of you and keep up the good work. I have already recommended Law offices of Rajiv S. Khanna to several of my friends. And many are now his clients.