Designer, using delegated measures

Best practices for using delegated measures 

Use a delegated measure when report users manipulate the measures in reports.
When they only need to refresh, view, and print their reports, the calculation may be simpler to perform in the report.
So use a delegated measure:
-          to replace multiple query aggregates.
-         on calculations that could give inaccurate results when calculated in the report (such as complex averages).
-         for measures requiring division.

When you create a delegated measure, make sure that you enter text to identify as such to users.
You can do so in the Edit Properties dialog box for the measure in the Description box of the Definition tab. This ensures that report designers can quickly recognize a delegated measure when they glide their mouse over it in a query.

Case in wich delegated measures must not to be used.

Do not use delegated measures when you apply a filter to an aggregated value from your query and further aggregate it within the report. Web Intelligence cannot determine how the filter affects the calculation of the delegated measure and returns the cell error code #UNAVAILABLE.

For example, do not use a delegated measure when there is a:
-       report filter on a dimension that is not in the dimension context.
-       report filter on the formula.
-       formula in the dimensional context of the measure.

However, for drill filters and for simple filters combined with "And" at the first level of drilling, the context takes the related dimension into account.

Business Objects Universe best practises