It's usually not at all a "cut" valley at all. A california valley is where you run a shingle verticle up the valley. Then you start your shingle rows off the edge of that vertical shingle in the valley line. Though most manufacturers allow this technique, starting at the edge of the valley may void the warranty for patterning issues. I suppose you can mark your rows and make cuts keeping the pattern thus making it a california "cut" valley, though I have never ever ever seen anyone do it this way. And if you were to actually cut in the valley what's the point you are not saving any time vs a traditional closed cut valley.
I really don't like the california style valley. Faster and easier seldom ever equals better. I try to always do what I feel is best. Same may argue the california valley is better because of the uninterrupted seal strip <shrug>