Well, I’ve been wondering that too Alison, because that was my understanding as well.
But if the reason is that the small tip of the sensor couldn’t read the level easily in such a small sample of interstitial fluid (and presumably there will be less glucose in the fluid than in blood) then the greater surface area of the new sensors may make it more possible for them to be more accurate and more ‘real time’.
Now I’m going to have to find out where I read that info…!