<<I put up Khri Hasten - and learn nothing
I believe khri base experience earned off of total difficulty of all khri being used rather than just individual khri, and then apportion it to your pools based on the relative difficulties of the individual parts from what I can tell. I.e. The difficulty of hasten just on it's own is not high enough to teach you any more, so you'll need to add another khri into the mix to make your total difficulty high enough to teach at that rank. Adding another utility khri will likely make utility move very well whereas adding an augmentation khri will let you train both skills at a slightly slower rate.
I think that eventually individual khri stop teaching once they reach a certain cap regardless of what they're mixed with, but I've never been high enough to test that personally.