Wrong total in table object

Thanks for your replies. After some investigating, I find the problem is not in a filter that I have, but in the behaviour of the table object. It happens that there are employees that don't show up in the table, because they don't have results for the columns I have in the table (like no billable hours and >0 workable hours, resulting in a blank value for billing ratio).

The issue is that apparently, the table computes the total line over only the lines that are visible in the table, not over all underlying data rows. This returns an incorrect total value (employees who have no billable hours but did have workable hours, should count for the overall billing ratio as well).

Is this a bug or by design?

The workaround, obviously, is to make sure there's always a column in the table object that contains values for all data rows.