I would break this into 2 separate calcs for ease.
the first you could call IsActive: Defined as > 2 widgets sold.
if SUM([Number of Records]) > 2 then 1 else 0 end
The second calc would read as follows:
when 1 then Total(SUM([Number of Records]) ) end
Try that... if the CASE statement doesn't work try switching it to:
if [IsActive] = 1 then....else 0 end
hope this helps,