You are correct that Zhou stated $140,000. My understanding is that the additional $40,000 includes funds frozen (rightly so) at ArumXchange. I would hope that Zhou would cooperate with authorities in apprehending and prosecuting the hacker.
Zhou has misinformed you. He has clearly stated here on multiple occasions that the $40,000 which AurumXchange has frozen is from a transaction he conducted on behalf of a friend and that those funds have nothing to do with the hacker. AurumXchange has frozen an additional $5,000 in funds which are presumed to be related to the hack and which are in an account which Zhou claims was opened without his knowledge using an email account belonging to him.
I realise that your legal involvement does not extend beyond ensuring the recovered funds are secured until control of the assets is passed into receivership and liquidation, but I wanted to clarify for you why you may be asked questions about why the amount recovered is less than what was promised by Zhou.