O1 visa choice. what is expert control, department of USCIS?

Anyone has the recent O1 visa timeline. Plan to COS to O1 with PP.

HR said that it will take 3-4 months to get back from expert control. Does it mean before I can submit to USCIS with PP, it will take 3-4 months to get an approval from expert control. it will definitely won’t work for me. anyone has experience, please advice. Thanks!!!