Before starting a project, I currently estimate project costs using Excel. I enter the tasks along with estimated effort. The spreadsheet will have several rules of thumb for high level estimates, such as Total Transition Effort will be 40% of the Total Development Effort.
I was wondering If I could use MS Project instead of Excel for this planning exercise. Then when costs have been finalised, the high level project plan can be given to the project manager who refines it further as the project progresses.
In MS Project, is it possible to automatically set one task's duration (E.g. Transition) based on another task/summary task's duration (E.g. Development)?