Anyone who knows a bunch about Thai boxers...

I know that almost all of them have aliases used to promote something commercial (usually the gym they fight for) that they go by... most people don't know their real name. I'm curious about one fighter in particular, named Ratanachai Sor Vorapin (you may remember him as the guy who got DQ'd for doing a judo kick when he got cut by an accidental headbutt and his opponent kept punching, instead of letting the referee call timeout and examine the cut: http://www.boxingscene.com/laput-outboxes-sor-vorapin-very-wild-ending--20183). He has a brother, named Ratanapol Sor Vorapin, who still goes by that name, but Ratanachai has since changed his last name of his alias to Singwancha. Does anyone know why?