There should be an option to have the aggregation used in the totals row be separate from the aggregation used in the rest of the rows. For example, the ability to have the aggregation for table values be an average, but the grand totals show as a sum of the averages above. Currently, you have to create a measure to do this, but it would be easier and more streamlined if you could control the aggregation showed in the totals row for each column value.
Merged with
Matrix/Table grand totals with Measures