Dolby Approved DTS Digital Surround Sound is not DTS 5.1.....
Those DVD do not need the approval of Dolby so that it could be DTS 5.1
Maybe it is Dolby Digital but not discrete such as DTS 5.1!
When Philippines start incorporating DTS 5.1 or THX in their theater, that will be nice (although I do not know if it is needed since Philippine movies are almost Love stories, Romance, and the like!)