FERC on Thursday approved revised rate schedules for two American Electric Power (NASDAQ:AEP) affiliates in Ohio to remove their RTO participation adders (ER23-855).

The order stems from a complaint filed last year by the Ohio Consumers’ Counsel (OCC) arguing that because state law mandates that transmission owners in the state participate in an RTO, the utilities should not be eligible for the adder. The commission agreed in December, requiring AEP to make a compliance filing recalculating its returns on equity for the affiliates without the RTO adder. (See FERC Orders Two Ohio Utilities Ineligible for RTO Adder.)

Under the new language, AEP affiliates Ohio Power and AEP Ohio Transmission would lower their ROE from 10.35% to 9.85% under the filing and revise the PJM tariff to specify that the adder does not apply to those companies.

The commission also approved a proposal in AEP’s filing to add language to the tariff stating that the companies have the right to receive refunds should federal courts invalidate the Ohio law, noting that there are pending lawsuits challenging the legislation on the grounds that it may pre-empt the Federal Power Act.

The OCC protested the filing, arguing that the notice provision asserting the right to collect refunds should not be approved, arguing it is out of scope, premature, and a violation of the filed-rate doctrine and rule against retroactive ratemaking.

AEP countered that the provision does not violate the filed-rate doctrine because it provides notice of a potential future rate change, which has been upheld by past court rulings. The commission agreed.

“If the commission’s determination in the December order is overturned, the inclusion of the notice provision provides sufficient notice under the filed-rate doctrine to permit Ohio Power and AEP Ohio Transmission to surcharge customers,” FERC wrote.