From what I’ve read in this thread, I think it’s the word ‘excessive’ that’s doing the heavy lifting. I don’t think there is any expectation that RDW has been eliminated, merely that it has been reduced to ‘normal’ levels. So Scotrail believe the conditions have been met that RDW should return to being paid at the standard rate rather than enhanced.
Sounds logical, and sensible.
As someone commented up thread it sounds like a poorly conceived, ambiguous agreement which is open to interpretation. Especially as the TOC is clearly 100% reliant on staff volunteering to come in on their days off.