According to the PMBOK Guide, the project scope is the work that needs to be accomplished to deliver a product, service, or result with the specified features and functions1. The project scope statement defines the project scope and documents the project deliverables, acceptance criteria, assumptions, and constraints2. The project manager is responsible for ensuring that the project scope is managed and controlled throughout the project life cycle3. If the contractor submits an offer for additional work that is already included in the initial project scope, the project manager should refuse the offer as it is not a valid change request and does not add any value to the project. The project manager should also communicate with the contractor to clarify the project scope and avoid any misunderstandings or conflicts. References:

1: PMBOK Guide, 6th edition, p. 154

2: PMBOK Guide, 6th edition, p. 157

3: PMBOK Guide, 6th edition, p. 171