THis is probably due to the formula in the running total where you are looking for the ID<>2. If there are nulls in there it is probably omitting them. If this is the case you can try 2 approaches.
Change the formula to:
isnull(table.IDfield) or table.idfield<>2
Not sure if that will work or not. If not try and create a formula to handle it by converting nulls then using that field as your condition.
Formula as "ConditionalCount":
if isnull(table.idfield) then 0 else table.idfield
Then use this in your running total conditional count as:{@ConditionalCount}<>2
Hope these work
then in your running total