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.