If the Project Manager has accepted a quotation for a compensation event and the Contractor has started the work associated with the CE, can the PM reassess the CE if he has realised that the Contractor has not allowed enough time and will now lose money on the CE?
No, clause 65.2 is clear that once implemented a CE quotation is not revised, the only exception being where a PM assumption used in the quotation has proven to be incorrect in which case a new CE is raised for the correction so, technically, the quotation is not actually revised.
Whilst it may seem unfair, doing so would mean that all quotations could be opened up because inevitably the quotation will not match the actual Defined Cost + Fee. This would undermine the whole intention of the change process.
If during actual implementation of the works there are deviations from the assumptions provided by the PM in how to assess the CE, then you can reassess the CE. The difference between the original assessment and the new assessment is a compensation event in accordance with 60.1(7)
Roger - just a point of clarity here whilst your sentiment is correct. You can revisit PM assumptions in an implemented compensation event but subtly that is a new compensation event under 60.1(17) rather than reopening the original implemented compensation event