457b and Keogh

A CPA that I work with asked me this question.  I don't do 457b plans, but here's what I think is the correct response - figured I'd get the experts here to check me on it.

He picked up a personal tax client who is a participant in government 457b plan.  The person is an attorney who also owns 50% of a law practice.  He is maxing his 457b deferrals ($30,500 in 2025).  The law practice has a 25% Keogh (I didn't realize anyone still had a plan called a "Keogh plan").  Is there any interplay between the contributions that has to be considered?  From what I can see, no; in fact, he could get a max employer allocation under the 457b plan (if allowable by the plan document), and then get his 25% under the Keogh.

Can I get a confirmation or a correction?  Thanks.

A § 401(a) retirement plan does not count § 457(b) deferrals in § 415 annual additions.

For example, an individual in her early 60s might have 2026 retirement savings like this:

(I assume my estimates of inflation-adjusted limits for 2026.)

457(b) deferral                        $36,500 (salary $40,000 as a retired government employee)

403(b) elective deferral           $36,500 (salary $40,000 from a university lectureship)

401(a) nonelective                   $90,000 (compensation $360,000 as a 50% owner)

                                                $163,000

Observe that the § 401(a) plan’s annual additions do not count against the § 403(b) account’s annual-additions limit. 26 C.F.R. § 1.415(f)-1(f)(2)(ii) https://www.ecfr.gov/current/title-26/part-1/section-1.415(f)-1#p-1.415(f)-1(f)(2)(ii).

In my experience, many government employees also have other employments and other businesses.

This is not advice to anyone.

Thanks!