There is an ambiguity in the additional conditions of contract (similar to Z Clauses), and the PM is required to issue an instruction under Clause 17.1 to resolve such ambiguity. However, it does not involve in any change of Works Information. Therefore, seemingly, it is not a CE according to Clause 60.1(1). Can the Contractor be compensated under any other Clause(s) in NEC3?
Not unless it fits one of the other reasons within clause 60.1 for being one. Clause 63.8 says the Contractor has deemed to have allowed for the one more favourable, but only when it is an ambiguity between two pieces of Works Information.
As a Contractor have you really incurred additional cost when you should have priced the Works Information? May be if you can describe what the ambiguity was between and how it has affected you we can say if there is any other avenue, but on the surface of it no.
This is a clause which has been changed in the 4th edition and a reason is that the Project Manager - indeed no-one party - has th power to change the conditions of contract, which include the Z clauses. A change to the Z clauses needs to be agreed between the Parties in accordance with clause 14.3.
In NEC3 I think you mean 12.3 Jon.
You’re right! Doing it from memory … …