The clause to look at is 63.2 (as well as the rest of clause 63 more generally).
In simple terms not much.
Why does any contract or contract option fail to deliver successful outcomes? I can give you lots of good examples as to where ECC option C has led to excellent results to both Parties on a project.
Deleted work is a change to the Works Information and therefore a compensation event under clause 60.1(1). You then follow the same mechanism to assess a compensation event whether it is a positive or negative change.
This one of the compensation events which the Contractor needs to notify at the end of each calendar month and which shows that the weather measurement in comparison to the weather data canbe shown to have occurred less frequently than once in ten years.
The contractual procedure is clear what to me is of even greater importance are the working practices between the Project Manager (planner) and the Contractor. What will they do every day, every week, every month to keep the programme upto date.