Per Section 12 and 12A of the MISO Tariff and BPM 005 Section 5.1.1, Market Settlements disputes must be submitted no later than 120 days from the Operating Day or 15 days after a resettlement of an Operating Day in order to be considered for further evaluation.
Settlements statements for an Operating Day are issued 7, 14, 55, and 105 days after the Operating Day. Settlements statements issued outside of the defined statement periods are considered Resettlement statements. Concerns related to any Settlements statements must follow the Settlements Dispute timeline described in Section 12 and 12A of the MISO Tariff.
For additional information please see BPM-005 Market Settlements
https://www.misoenergy.org/legal/business-practice-manuals/