I certainly wouldn't imagine that any extra buttons are needed. The issue seems to be related to the extreme sensitivity of the knob, coupled with the necessary ability to scroll through a vast amount of data (without requiring the user to spin the knob like crazy to get to where they need to go).
One possible solution:
Introduce a 1 or 2 second reaction delay, so when the delay time knob is touched, the current setting flashes at the user, before the actual adjustment begins.
