It can ake sense if you look at it fromt he point of view that Zero-G Adaption covers all aspects of moving and working in zero/trace-G environments, where as Zero-G Combat is purely geared towards bracing techniques for firing weapons and swinging punches/kicks, not getting tot he combat inthe first place. A more limited, but more effective (bigger modifier reduction), training program.
That said, I can see your point of view too, and either is equally valid.
Shane