Include the granularity attribute of the time dimension in all the aggregations of measure groups with only semi-additive measures
This rule analyzes aggregation designs in measure groups that contain only semi-additive measures to verify that the granularity attribute of the time dimension has been included.
You should include the granularity attribute of the time dimension in all of the aggregations. Queries to semi-additive measures are always evaluated at the grain-level of the time dimension. For example, the calculation engine will automatically calculate a query for the inventory count in Q1 at the month level, if the grain of the time dimension is months, and it will then compute the result for Q1 "on-the-fly". Because of this query time behavior, aggregations above the month level will never be used.