Difference between soft sleeper and luxury soft sleeper?

A soft sleeper compartment has four bunks, two upper and two lower. And the luxury soft sleeper compartment has two bunks, an upper and a lower. In the luxury soft sleeper compartment, there are comfortable sofa, closet for luggage, thermos, LCD TV, etc. The highlight is that each compartment has a toilet. Facilities in luxury soft sleeper carriages are the same as those of the soft sleeper carriages. But the price for luxury soft sleeper is more expensive than that of the soft sleeper.