I am a noob myself so do not take my word alone. but I think and again I am a noob 1 is a bi lateral distribution and one is a uni lateral. Of course I am going the 18th for the curves and surfaces class so if I am wrong ignore me it just I have seen this myself and I think that is what I saw but with out the CMM in front of me I cannot say for sure. Sorry if I confused you more
