You chose to call the Hong Kong C.E.O " Mr. Luang".  Sorry but this is wrong and both you and he lose face because of it.

Chinese family names come first, so in calling him Mr. Luang on first acquaintance, you are getting on to first name terms far  too quickly  and without invitation.  This shows disrespect, which is not the best start to a business relationship. The correct way to address him on first meeting is "Mr. Kim".