If it is anything like the transport fleet in the RAF when I was in. If a tech call was made then the crew will remain in CDT until the tech delay would put them out of it should it the frame come up. I.e. if the CDT was 14 hours, (assuming starting 2 hrs before chocks and 2 after landing), then the crew could just make it anything further delay and they would be out of hours for that trip.