There are two work arounds. Work around one. Create a custom bds layer and create a new field variable by adding in the offending variable into the calculation too box by itself, e.g. ([MEDNW_CY] - Median Net Worth). Then add this variable into a custom report and the output will be correct.Work around two. Create two custom reports. In the first report, don't include the offending variables. Run this report using the custom bds layer. In the second report include only the offending variables. Run this report using the ESRI Block Group bds layer.