IIRC there is a way to set up a new paramater "snap" value. It's been a while since I read about it but I think it's in the Right Click options. It sets the current value as the default point where the control snaps to on double clicking (instead of, say with a fader, 0db you could set it to -6db or whatever).
I may have that totally wrong but there is a way similar to what I described that retains non default values.
And no... I'm not talking about "Offset" mode.
However James' idea of looking at the first node at the start of an automation write action seems the simplest way.
Cheers.