Kong is loose with the gamerscore points
The real question is, who oversees the allocation of points? Developers could sell a title they know is crappy just by filling it full of easy points. What if 25 to Life came out on 360 chocked full of easy points? There is a real danger of gamerscore inflation where, depending on which games you play, the time and skill spent might not be commensurate with the points rewarded. Hopefully the disparity evens out as more titles are released.
(Image is from Xbox 360 Achievements.)