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.
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