Here's my main concern. This might not be a problem for lower end characters but assume you're a character that takes a considerable amount of UE to train endurance.
When you get your chrome loadout to the limit, that means to reduce your PDS, you'll have to spend a lot of UE into endurance to get that PDS level down. If endo had a flat PDS level reduction, then I could take endo all the time and simply load more chrome into myself without risking going full borg -- avoiding what the curve is supposed to even do (make things harder), for the simple price of a drug.
If this can be avoided somehow I am all for it.