See clip from Attorney Rajiv S. Khanna's conference call video that addresses this question.
The idea is once an I-140 is approved under any category EB-1/EB-2/EB-3 the priority date becomes the property of the employee. Whether the employee goes to work for a different employer or a different job completely or like a different job where you go from being a IT professional to a civil engineer you would still carry your priority date. This is not AC21. AC21 requires same or similar job but that also requires I-140 approval, I- 485 pending for 180 days. This is not that case. The priority date transfer from EB-2 to EB-3 requires only the I-140 is approved.
Hence the answer to the question is YES. If you get a job with the same employer or with a new employer that requires a masters degree or bachelors plus five year experience type of qualifications and your priority date will remain the same. The difference between AC21 and priority date carry over date is this: In AC21 you do not have to re file the green card. You can take the whole green card and take it over to a same or similar job if you’re I-140 is approved and I- 485 is pending 180 days. But in the priority date transfer you carry forward nothing. You only carry the priority date and it can be ported from EB-2 to EB-3/EB-1 to EB-2/EB2 to EB-1 it doesn’t matter. There is no requirement that the job that you are filing for is same or similar. That is the difference between AC21 and priority date transfer.