NEC3 states 'notification' and NEC4 states 'notification and certificate', although in many respects that should probably also include 'instructions' and 'acceptance'. What the clause aims to achieve is to not allow important communications to get 'lost' (overlooked) amongst other more 'general' communications.
Assuming these are quotations for notified CE's, in response to a PM's instruction, then clause 62.6 gives the Contractor the right to notify the PM where a response has not been given within the stipulated timescales. I see no reason why your singular notification cannot relate to more than one CE quotation, as the notification is communicated separately, in accordance with clause 13.7, albeit relating to several different quotations, although the notice is given for the same contract procedure.
Where you are notifying on different subjects, for example the lack of response to a CE quotation and also an early warning, then these should be separate as they would lead to different responses and there is the potential for one of these to get 'lost' or overlooked.
Assuming these are quotations for notified CE's, in response to a PM's instruction, then clause 62.6 gives the Contractor the right to notify the PM where a response has not been given within the stipulated timescales. I see no reason why your singular notification cannot relate to more than one CE quotation, as the notification is communicated separately, in accordance with clause 13.7, albeit relating to several different quotations, although the notice is given for the same contract procedure.
Where you are notifying on different subjects, for example the lack of response to a CE quotation and also an early warning, then these should be separate as they would lead to different responses and there is the potential for one of these to get 'lost' or overlooked.