RBowers@nyiso.com writes to the NYISO_TECH_EXCHANGE Discussion List:

The settlements curently posted for September 28-Version 2 & 29-Version 1,
2001 are not accurate due to problems encountered with some data files for
those dates.  As a result, some customer balancing energy is incorrect and
residual adjustments for those dates are artificially inflated.  The NYISO
will be re-running those billing dates as soon as it is feasible to do so.
The NYISO apologizes for any inconvenience caused by this problem.

Regards,
Randy A. Bowers
Manager-Customer Settlements