Do you think that the critical path change during the project,
If you Say no, that’s mean you like to use the method of (impact as planned) for delay analysis.
If you say yes, that’s mean you like to use the method of (Time Impact Analysis) for delay analysis.
sure that the critical path change during the period of the project, and it’s not fair to use the first method (impact as planned), because this method is built on the idea of to see the impact of the delayed activities in the base line program, which is have a critical path not reflecting the true critical activities on project anymore at the time when this delay occurred.
In other meaning, the critical path which is in the (updated progress program) is more accurate and reflects the actual critical activities on site.
So, take care of using the (impact as planned) for delay analysis even if it’s agreed method or old method