“13. The entire object of the said amendment is to stall filing of applications for amending a pleading subsequent to the commencement of trial, to avoid surprises and the parties had sufficient knowledge of the other's case. It also helps in checking the delays in filing the applications. Once, the trial commences on the known pleas, it will be very difficult for any side to reconcile. In spite of the same, an exception is made in the newly inserted proviso where it is shown that in spite of due diligence, he could not raise a plea, it is for the court to consider the same. Therefore, it is not a complete bar nor shuts out entertaining of any later application. As stated earlier, the reason for adding proviso is to curtail delay and expedite hearing of cases.”