Roll Up the Custom Field in the MS Project Professional 2010

By default, Project 2010 does not calculate values for custom fields for summary tasks or for the rows containing rolled-up values for groups. However, you can choose the type of calculation for summary tasks and group summary rows or use the formula you defined for the field.
If you select the Rollup option, you can choose from several built-in calculations in the
Roll-up drop-down list, including the following:
● Average The average of all nonsummary values underneath the summary task or group
● Average First Sublevel The average of all the values of tasks one level below
● Maximum The largest value of all nonsummary values
● Minimum The smallest value for all nonsummary values
● Sum The sum of all nonsummary values underneath the summary task or group
To do this:
1. Open the custom fields dialog box by right click any field header and click custom fields.
2. Create your custom field and give it a name.
3. Click the roll up option.