George,
 I would suggest that the necessary language be added to the Special 
Conditions block of the Transaction Confirmation.  I would suggest the 
following language be inserted in each applicable Transaction Confirmation.

"Notwithstanding anything to the contrary otherwise contained in the 
sentences previously added to the end of Section 13.5, the parties agree that 
the price to be applicable with regard to any volumes outside of the +/-10% 
tolerance shall be the Gas Daily "Daily Mid-point" price for the day 
following the day that the parties discover the existence of volumes outside 
of the +/-10% tolerance."