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

Dear Market Participants:

On the November 1999 & December 1999 Transmission Customer Monthly
Statements many customers have noted under the "Energy Settlement" section
for "Forward Energy" a change in MW-Hrs with no associated change in dollar
amounts.  This is because of a correction in the sign convention for the
MW-Hrs related to external generation transactions (transactions from a
proxy bus to the NYISO reference bus).  For all other types of transactions
the NYISO charges customers the appropriate TUC or LBMP  based on the MWs
that flowed, but for external generation transactions, customers receive
payments from the NYISO, and therefore these types of transactions have an
opposite sign convention.

The dollars associated with the external generation transactions have
always had the proper sign convention, but the MW-Hrs have not.  On
01/17/2000 this sign convention was corrected for all billing months going
forward resulting in the correct MW-Hr values being reported from February
2000 to date.  However, November 1999 - January 2000 did not have the
proper MW-Hrs reported on the Transmission Customer Monthly Statements.
With the latest settlement adjustments posted the MW-Hrs are being
corrected with the proper sign convention.  Transmission Customers will see
similar changes in their forward energy MW-Hrs for January 2000's
settlement adjustment.

If you have any questions please contact your Customer Relations
representative at 518-356-6060.