Because many older claims were found ( on at least two occasions ) to have been incorrectly refused by the banks. Each time the F.O has ordered that previous claims be re-visited and each time the banks have demanded fresh claims to be lodged ... and, I suspect, are still refusing valid claims.
So, whilst there is official uncertainty as to whether PPI has actually been correctly dealt with, the IP is under an obligation to keep on that particular ball.
My opinions are merely that .. opinions based on experience. Always seek professional advice.
IVA Completed 23rd July 2013 .... C.C. 10th January 2014