The contract does indeed permit such an approach - although I don't feel this is a trick or a ploy on the Contractors part. At the end of the day, if they have not used all of the time risk allowances they had allowed for on the critical path then their planned Completion (which should be shown as a separate milestone) sounds in this case that it has moved forward by two weeks. This has created a difference of two weeks between "planned Completion" and the "Completion Date" which the guidance notes specifically calls "terminal float". The Contractor owns such float (like they do time risk allowances) and is retained in the assessments of future compensation events i.e. if a future CE moves planned Completion by one week Completion Date also moves by one week - maintaining the terminal float that has been created. If a Contractor suffers a one week delay which is their liability which moves planned Completion by one week then the terminal float period by default would now only be one week.
Free float/total float is float on non-critical activities which is shared by both Parties but is not relevant in the example you give here.
Free float/total float is float on non-critical activities which is shared by both Parties but is not relevant in the example you give here.