The row over the aptness of the estimated amount of notional loss to the exchequer in the 2G scam refuses to die down. Now Vinod Rai, the CAG is all set to depose before the JPC looking into the scam. Rai will have to explain the basis of 2g loss calculation and also validate the Rs 1.76 lakh loss figure Vinod Rai must also explain why the same loss was estimated and pegged at a much lower number by a member of his team and the CAG must also explain if figure was notional or real.