I140 SII amendment with I485

my EB2 date is current. We filed I140 SII amendment + 485 + EAD + AP concurrent. I received all receipt notices. Also received fingerprinting approintment.
We want to upgrade I140 amendment SII in premium. Question is - is there any benefit of filing I140 premium upgrade AFTER fingerprinting appointment? Is following scenario possible?

After fingerprinting is done, we file I140 premium upgrade - USCIS has 15-20 days to adjudicate I140 - during adjudication they see that my fingerprinting is done so the officer working on my file approves everything and I get green card faster.

This is a probability for sure.

so you mean to say is that we should not file i140 upgrade to premium BEFORE fingerprinting and instead file it after fingerprinting is done?

Doing it before or after is your choice. I am agreeing with you that there is a chance that your I-485 may get adjudicated faster assuming the I-140 & 485 are being processed by the same officer.
I am also assuming you submitted the medical with I-485. If that’s the case your AOS file should be documentarily completed once biometrics is done unless there is any further information/documents that USCIS may need and request via RFE.

I have similar case . My emp has filed in regular process ( I 140+485+EAD + ap ) along with medical . I got all receipt . I completed biometric . My employer told me to wait for 2 to 3 months before they upgrade 140 in premium . I want to do premium.

I’m not sure why he is telling me to wait for months to covert 140 regular to premium .

What’s the benefit of waiting few months. ?

Is yours also SII amendment case?
in that case you can upgrade I140 to premium as soon as your lawyer gets I140 filing receipt notice for you. (note that In case of I140 you will not get any receipt but your lawyer will)