What would take to change from actual cost to estimated cost of project (tipcs)??

Estimated and actual costs co-exist in Baan.

You cannot calculate your actual costs until you finished your project.
After all, not until you know the exact amount of material and operational costs that were required are you able to determine your actual costs.

However, if you want to know how much a project will probably cost you before you start manufacturing, Baan can provide you with an estimated cost, based on BOM and routing.

This parameter is part of initial set up . Once there are projects with active status , it's not allowed to modify. If one changes in GTM , then all existing transaction calculation and current project calculation will go wrong.

So practically it can't be changed.