Assuming you're using a DCount in a query to retrieve the number of tasks tested (as in my previous example file), you could try something like the following;
TasksTested: DCount("*","Table1","Worker_ID=""" & [Worker_ID] & """ And MT_Type='original' Or Worker_ID=""" & [Worker_ID] & """ And MT_Type='rework'")
This may run a little slow, you'll have to test it to see if performance is acceptable. There may be better ways to approach this, but I couldn't say because I have no idea what the real structure of your application is.