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

Dear Market Participants,

The NYISO is in the process of migrating the NYISO billing system to a new
server.  Customer advisory billing statements for July 15 - 17 may not
contain metered megawatthour data supplied by market meter authorities.  In
the absence of metered megawatthour data, the billing process for Balancing
Market settlements is performed using instantaneous integrated data from
the NYISO Performance Tracking System.  Completion of this migration is
anticipated for late evening of Wednesday, July 18.  Market Participants
are asked to refrain from submitting billing inquiries for July 15-17
billings until further notice.  The NYISO will rerun the aforementioned
billing dates as soon as the migration has been completed.  The NYISO will
inform the market when this migration has been completed and indicate when
rebillings for July 15-17 may be expected to be posted.

The NYISO apologizes for any inconveniences caused by this project.

Regards,
Customer Relations
518-356-6060