My company is undertaking a project for expansion of its existing plant. Engineering, procurement and construction have been assigned to different contractors. We are now in the process of preparing master shcedule encompassing all the three phases. So, we are now facing problem in assigning %age weightages to different phases. If we use the standard yardstick of respective cost then because of cheap labour, the cost contribution of construction cost is coming out to be only 9.5% of the total budget. As per the schedules submitted by E&P contractor, procurement would be completed around one year before mechanical completion of the project. So if we go by cost for around a whole year out of 3 years span of project, we would be left with only 9% which doesnt sound appropriate. Could anyone give me a clue on how these apportionment of weightages are done.