I am not sure I really follow the point here. Changing a rate doesn't always mean you will change the time allowance as well.
However, if the point is that the parties are really agreeing that there was a mismatch between the work and how it was described leading to a need to change the rate then I think you would look at the activity as a whole and consider whether the same description deficiency had a time impact as well. If it did you alter the whole activity bar and assess, once the programme is updated, whether planned Completion changes.
However, if the point is that the parties are really agreeing that there was a mismatch between the work and how it was described leading to a need to change the rate then I think you would look at the activity as a whole and consider whether the same description deficiency had a time impact as well. If it did you alter the whole activity bar and assess, once the programme is updated, whether planned Completion changes.