TASK REPORT: Actual Duration is greater than Planned Duration

I'm not entirely sure that you can perform calculations like this in a filter, so it's probably best to use a calculated field on all your tasks that performs this math before you get to the report, so that your report merely looks for whether this field has the right answer. In other words, your task custom form would have a field on it subtracting actual from planned duration and giving an answer only if the difference is more than 5. Then the report would just filter for the calculated field.

while you cannot use an expression in the filter when comparing a FIELD, you can group the report into brackets, and have them collapsed so that you just open up the ones you wish to see...

In the following group text I created groups for 0 - 5 days, 6 - 10 days, 11 - 25 Days, 26 - 50 Days, 51 - 100 Days and > 100 Days

Code is textmode ==>

textmode=true
group.0.iscollapsed=true
group.0.valueexpression=IF(DIV(SUB({actualDurationMinutes},{plannedDurationMinutes}),480)<5,"0 - 5 Days",IF(DIV(SUB({actualDurationMinutes},{plannedDurationMinutes}),480)<10,"6 - 10 Days",IF(DIV(SUB({actualDurationMinutes},{plannedDurationMinutes}),480)<25, "11 - 25 Days",IF(DIV(SUB({actualDurationMinutes},{plannedDurationMinutes}),480)<50,"26 - 50 Days", IF(DIV(SUB({actualDurationMinutes},{plannedDurationMinutes}),480)<100,"51 - 100 Days","Over 100 Days")))))
group.0.valueformat=HTML
group.0.linkedname=direct
group.0.name=Duration Timeframe