A ProjectPlanData can include one or more ProjectEstimation . Each of this ProjectEstimation represents different estimation scenario for the project. For example one of the Project Estimation may be with an expert team and other with a mixed team etc..
One of this ProjectEstimation has to be set as default for the project. It means, that the default ProjectEstimation is the valid estimation for the project. An ProjectEstimation can contains one CocomoBase and one ore more CocomoSub . The CocomoBase is the the sum of Sub Estimation, which also means total estimation of the project. The Sub Estimation enable you to estimate each logical or technical sub systems of the counted application or application of a project separately.
You can specify the Scale Factors in the Base Estimation for the whole project/application. You can also specify the Cost Factors for each Sub System or Application in the Sub Estimation separately. This feature enables you to estimate each sub system of an application or each application of the project precise and correctly.
For example: There are application A and application B to be developed in your project. Each of this application will be developed by different team on the different platform with different language in the same project. There some factor like scale factors has to be set for whole project. You can adjust this scale factors in the Base Estimation for the whole project. You can also create two Sub Estimations for the application A and application B. In this two Sub Estimation you can adjust the Cost Factors for each application system separately. Finally you have two separated sub estimation for each application and a Base Estimation for whole project (application A + application B)
Project Plan Data