We’re engaging subcontractors for early contractor involvement. Will the ECS option C with X25 be an appropriate contractual and payment mechanism to complete Stage 1 and proceed to Stage 2 for one of the Subcontractors?
Would the Stage 1 also be susceptible to pain/gain?
Presumably at the time of writing the subcontract the Works Information will only be for Stage 1 (ECI). How do you update the Works Information for the subcontract for continuation into Stage 2?
In principle there is no reason why you can’t amend X22 from the ECC to make it work with the ECS. You would need to be careful how you did this to ensure it aligns with your main contract and so that you limit the Subcontractors role to advising on Stage 1 and Stage 2 of their Scope and not the whole project.
Note that Stage 1 has no target, this only applies to Stage 2. Stage 1 is like a main Option E contract in that payment is based on Defined Cost plus Fee.
The Scope needs to define your requirements for both Stages 1 and 2, and as such it would only need updating if your requirements changed. A notice to proceed to Stage 2 is required in order for Stage 2 works / services to be progressed.
See also this article here which might be useful : https://www.jonbroome.com/blog/january-2016/the-new-nec3-early-contractor-involvement-clauses