Contractor requires Professional Consultant to prepare those claims which have significant cost and time impacts to Contractor. Owners trusts claims prepared by Professional Consultant/Third Party. Professional Consultant, for carrying out schedule analysis, needs from Contractor an un-impacted Level 3 Schedule in Prima Vera and historical evidence on Owner caused delays monthly basis. Concurrent delays are identified. Excusable and non-excusable delays are also identified by the Professional Consultant. On any delay that has occurred and impacted the schedule in the critical path, Contractor should have served contractual notice in written letter form (not emails) as required by provisions in the Contract, without which the claim pertinent thereof fails to qualify.