Sum Numerical Custom Fields in Reports

Today, in a Report, when I add a column for a built-in Wrike field that is numerical in nature, such as "Time Spent," the report displays a sum at the bottom of that column and also a sum for each grouping in the report. It would be great if reports would also display sums for custom fields that are numerical in nature.

Our organization's use case for this is that we have a custom field that we use to apply a value for certain tasks. We would like to be able to see the total value of tasks completed by an individual in a given week.