The hacker's name "Jia Cheong Tan" actually includes phonics from both variants of Chinese from China, Singpore and Hong Kong region, hence no way it is a name of a real person, so the name probably don't indicate anything. However, since the Hong Kong and Singapore variants is rarely used, the group behind the hacker probably has good knowledge of Chinese linguistics. Either way, the fact that the hacker's account shows GMT+8 and that the hacker's activity is mostly in Southeast Asia working hours (read GMT+8) would only make sense if the hacker is originated from Asia countries. I doubt that group of people behind the hack can consistently stay late night for 2+ years just to fake the timezone.