If a contractor provides a quotation for an acceptance of a defect which the project manager does not agree with, can the project manager subsequently make an assessment on this quotation?

Answer

I assume you are following the provisions of clause 44, which deals with the acceptance of defects. If this is the case, both the project manager and contractor must agree to be prepared to consider the change. Either the project manager accepts or rejects the contractor’s proposals in terms of reduced prices, an earlier completion date, or both.
There is no express provision for the project manager to assess; the process is not governed by the rules for compensation events. There must be agreement, otherwise the clause is inoperable and the contractor must correct the defect.