If your spin is upright-change foot-upright, that is CUSpB, which is 1.5. If your spin is sit-change foot-upright, that is CCoSpBV, which is 1.28. How is it that the harder spin has a lower base value?
I think it's because of the very specific spin requirements at the higher levels that require single position spins. You'll notice a flying camel spin (FCSpB) also has a higher base value than a flying combination spin (FCoSp).