cost control in the project

correct Rami, this is the correct process. In my case, due to I normally use a fixed price contract for general contractor (like you I'm in civil construction field). For this reason the process you describe is not applied to general contractor (after contract signature off course) but more effectively for minor items (furniture, wood finishes etc.) and change order for contingency not included in the general contractor contract. Concerning minor Items I think is better to have an high level estimate at the beginning which you can improve when it is necessary (these items normally are necessary 1 - 1,5 years after construction start - and costs can change in the meantime or some of them are not in production anymore)

Glad to know we are in the same field. In case of FP Contracts, we usually estimate and prepare a budget before sending out tenders for bidding. When you have FFP, I agree its difficult to do savings and sometimes changes are huge but usually we use FP with Incentive.

thanks Krishna for your contribution, may you briefly describe the method through WBS?
many thanks

As you know, in WBS & WBS Dictionary all details including cost, time, resources, risks, milestone etc. of the work package is very clearly worked out after a considerable thought & discussion. During execution, we keep on comparing the actuals with WBS deliverable details to assess whether the project is on track or not. In nut shell we keenly monitor and very concerned about the schedule delays and cost overrun if any. Here WBS is used as base line or reference document for project performance on cost & schedule front.

As you know, in WBS & WBS Dictionary all details including cost, time, resources, risks, milestone etc. of the work package is very clearly worked out after a considerable thought & discussion. During execution, we keep on comparing the actuals with WBS deliverable details to assess whether the project is on track or not. In nut shell we keenly monitor and very concerned about the schedule delays and cost overrun if any. Here WBS is used as base line or reference document for project performance on cost & schedule front.

Hi Krishna, you are right that WBS dictionary contains mayn attributs that are elaborated over time, including cost estimates. The WBS/dictionary is mainly used as scope baseline. A cost baseline or budget is developed out of this and the schedule and can include risk contingencies, uplifts etc., so it might be (will be) in sum more than the WBS dictionary estimates.