Under the ECC form, the simple answer is that the Project Manager can make their own assessment of the compensation event, under clause 64.1, if they decide that the Contractor has not assessed the compensation event correctly in a quotation.
Clearly the word 'correctly' is key here and relates to the application of various principles, including; the submission of appropriate details, the division of actual and forecast Defined Cost, inclusion of appropriate risk allowances, correct application of 'Defined Cost' in the assessment, reflecting the actual scope of the compensation event and any other consequences that are 'due to the compensation event',
Whether the Contractor's initial assessment is actually 'correct' could be a matter for an adjudicator to decide, where disputed, so you need to be certain that any Project Manager's assessment is not just based on the view that it is 'an excessively large claim'.
Clearly the word 'correctly' is key here and relates to the application of various principles, including; the submission of appropriate details, the division of actual and forecast Defined Cost, inclusion of appropriate risk allowances, correct application of 'Defined Cost' in the assessment, reflecting the actual scope of the compensation event and any other consequences that are 'due to the compensation event',
Whether the Contractor's initial assessment is actually 'correct' could be a matter for an adjudicator to decide, where disputed, so you need to be certain that any Project Manager's assessment is not just based on the view that it is 'an excessively large claim'.