@QuyLe in the co-term model there is one consistent end date for every device in the organisation. Each licence counts as a number of 'points' and when you add them up you get the end date.
For example: Org has one wireless AP with 6 months left and adds one more wireless AP
6 months + 12 months = 18 months. 18 months / 2 devices = 9 months each
If the end point was the end of December 2022, it would now be the end of March 2023.
Different devices add more or less 'points'