I'm guessing they want to free up the paramater control (which would otherwise be overtaken by the envelope).
That's partially why I mentioned finding a plugin of some some that could control volume without using the fader volume for the envelope.
I should have done a test using the clip automation before closing Sonar for the night.
However... if this isn't possible one thing I've used in the past for a similar scenario is just using Bounce to Track into a new track and dragging the resulting clip into a new take lane in the original track (and of course deleting the newly created track and removing the effect/envelope that I'd just printed... and muting the original take so I could revert back easily if need be).