If you manually set the count to return by using SetInlineCount, the QueryableAttribute action filter overwrites it, so your total is never returned in the response.
Confirmed as a bug by "raghuramn". A workaround exists in the discussion.
Link to discussion: https://aspnetwebstack.codeplex.com/discussions/439302#post1026333
Comments: Fixed: https://aspnetwebstack.codeplex.com/SourceControl/changeset/c78429abb3287dfd91e9cb4152179d5aee11c42e
Confirmed as a bug by "raghuramn". A workaround exists in the discussion.
Link to discussion: https://aspnetwebstack.codeplex.com/discussions/439302#post1026333
Comments: Fixed: https://aspnetwebstack.codeplex.com/SourceControl/changeset/c78429abb3287dfd91e9cb4152179d5aee11c42e