The word “may” is used as it does not make it obligatory to notify the Project Manager that he has failed to respond, but if the Contractor does not notify this then they can not trigger the “deemed acceptance” loop which makes it deemed accepted if the fail to respond to the notification (that they have not responded). It is the Project Manager who has failed here.
If they fail to notify then it remains not agreed yet that this is a compensation event and the Contractor can not move forward with the quotation and is not clear on their likely liability.
This same loops appears when the Project Manager fails to respond to a quotation, or fails to make their own assessment when they said they would. In each of these instances the Contractor can remind(notify) of the PM’s failure to respond and after a further two weeks of silence their original quotation and assessment on time would now be deemed accepted by default.
These are the only three deemed acceptances in the whole of the contract and is trying to give the Contractor some recourse if the PM fails to carry out their contractual obligations.