There is an HW category strangely under Pool URLs that says 3. That can't be right can it?
That's the one. The first guy coded it in that position and it stuck.
Is there some other formula I should be using to find the error rate? As far as I can tell, it should be HW/(diffA+diffR+HW)*100.
Off the top of my head it would be HW / Diff1 * 100 if you have Diff1, else HW / DiffA * 100 will give you a reasonable approximation. Do you not have a % box in the last row of DiffA calculating this though?