They could have easily changed the wording of clause 15.1 to read (with new words in CAPITALS):
The Contractor and the Project Manager each give an early warning by notifying the other as soon as either becomes aware of any matter which could:
- DECREASE or increase the Prices OR DEFINED COSTS,
- BRING FORWARD OR delay Completion,
- BRING FORWARD OR delay meeting a Key Date or
- ENHANCE OR impair the performance of the works in use.” (which would address the benefits point)
These opportunities could be for changes to the Client’s or Contractor’s Scope, Contractor’s design or programme. You would also need to tweak the first bullet of clause 15.3.
Seeing as the Steering Group forgot to do it, what’s stopping you (Clients) introducing these words to get better projects?