We need to prove that the delays are coming from the client. and if there are delays from the contractor side it is much less than client delays. Accordingly, we put the client delays on the baseline to have impacted as-planned schedule which is P1. Let us say this gives us 100 days + project original completion date.
Now we want to compare the planned scenario (Impacted as planned) with the actual scenario (Progress update) to see if there are more delays from the contractor side or mitigation actions which should be considered in the evaluation of the claim.