I guess as they're separate patches, their play ranges have to be adjusted one at a time. Imagine if you loaded (say) a bassoon patch and a piccolo patch: their sample mappings are completely different, so any range extension applied to one would be meaningless for the other. To edit eight DS patches' ranges simultaneously, they would have to be seen by the VI software as 'special case' patches, which I imagine would require a lot of programming work for VSL.
BTW, you can copy some paramaters (such as Mixer settings) from one patch to another, which saves a lot of time.