Didn't read the whole thread yet so I'm not sure if the question has been answered yet, but ski companies rarely have the actual advertised length of their skis. Most companies measure the material before it goes into the press, so the length comes out a little different.
Anyway, AS FAR AS I KNOW, a few years ago K2 decided to make their POW SKIS ONLY true to size, and the park skis still run a bit long. My 174 recoils are actually more like 176.
Now a lot of other companies may run shorter, thats why my 174 k2's are the same length as my friend's 183 atomics.