Regulation E does conflict with ACH rules on stop payment rights. In some ways, ACH rules are more protective (the types of EFTs that have stop rights under Reg E is very limited; all EFT debits can be stopped under ACH rules). But Reg E is more protective of a consumer with regard to the termination of the stop order. Regulation E has no termination provision at all. So, Reg E trumps the portion of ACH rules Section 8.4 that provides for termination of a stop order when the payment has been stopped, but only with respect to recurring transfers authorized by a consumer with a single standing order ("preauthorized electronic fund transfers from an account," in Reg. E-speak).

The ACH rule prevails for other transfers from consumer accounts.

Ironically, the ACH rule (at 8.5) covering stops on non-consumer accounts only includes the 6-month expiration rule (probably ported from the UCC rule on check stops). For some reason, NACHA isn't consistent between two adjacent sections of its rules.

The reason for the "until stopped" provision in the consumer stops rule is probably the NACHA prohibition against reinitiation of a stopped entry. One wonders whether that prohibition is honored more in observance or in non-observance. I can only suggest that if an Originator reinitiates a stopped debit against a consumer's account and the RDFI lets it through based on the NACHA rule at 8.4, the Originator could be accused of a rules violation, but the RDFI could be cited for a Reg E violation. I know which side of that discussion I'd want to be on.

Two last thoughts: You aren't likely to get into trouble by conforming to the Reg E standard for all stops on ACHs. Leaving them on forever is probably overkill, but leaving them all on for six months makes sense to me. Having one standard for stop expirations is easier than managing two or more rules.