S-Corp and whether or not to add ROTH provisions for 2026

The SECURE 2.0 final regs provide Plans are not required to add Roth provisions to continue Catch-up contributions in 2026; they also provide a "safe harbor" provision that can be added to the SECURE 2.0 Amendment for Plans that do not offer Roth contributions, to avoid tripping over the Universal Availability requirements (similarly situated employees for Catch-Ups) where the Plan Sponsor is Self-Employed (or Partners) and does (or could?) have a Non-Highly Compensated Employee (50+) who is a High Paid Individual ("HPI") for purposes of the 2026 Roth Catch-up rules. To avoid discrimination, the Plan can essentially "prohibit any HCE with any "compensation" in excess of the HPI FICA threshold from contributing Catch-up contributions in the following year. In doing so, you avoid the discrimination issue.

My questions are:

1. Can this "safe harbor" provision state it is only effective for the Plan Years in which there exists a Non-Highly Compensated Employee (50+) who is an HPI? If so, can the HCE owner therefore contribute pre-tax Catch-up?
2. Can or must an S-Corp Plan Sponsor incorporate a similar "safe harbor" due to the nature of S-Corp "control" over W-2 wages (albeit they should be reasonable) and dividends?
3. Can the spouse of the S-Corp owner continue to make pre-tax catch-up when prior year W-2 is less the HPI FICA threshold?  It seems to me they can since income is not "attributed" (therefore no effect on whether or not they are an HPI).

Thank you.

For anyone who might help cheersmate reason through those questions, here’s the final rule:

https://www.govinfo.gov/content/pkg/FR-2025-09-16/pdf/2025-17865.pdf.

The rule paragraphs cheersmate mentions [26 C.F.R. § 1.414(v)–2(b)(2)-(3)] are on page 44549 [page 23 of 27 in the pdf].

I just happened to be looking at this issue and my initial thoughts are:

I doubt a plan provision can be made operative or inoperative, such as whether Catch up Contributions are allowed, based on the annual census data.  That being said, I think you could accomplish the same, without violating the universal availability rule, by actually amending the plan each applicable year to add or eliminate the Catch-up Contribution feature (yes a PIA).  I would think the same would apply in the S-Corp situation.  Without looking into it too much, I think I agree with #3 as well. Spouse still an HCE, just not an HCI.