While I’m good on fiduciary law, I’m no more than a novice on qualified-plan rules. But using your expertise, consider these points:
Elapsed time doesn’t measure service; it measures time that elapses between a beginning moment and an ending moment. The ending moment is “[t]he date the employee severs from service[.]” 26 C.F.R. § 1.410(a)-7(a)(2)(ii) https://www.ecfr.gov/current/title-26/chapter-I/subchapter-A/part-1/subject-group-ECFR686e4ad80b3ad70/section-1.410(a)-7#p-1.410(a)-7(a)(2)(ii)
A perhaps related point of tax law treats someone who has been a self-employed individual as continuing to be a self-employed individual even if a year’s earned income is zero or negative.
The term “self-employed individual” means, with respect to any taxable year, an individual who has earned income . . . for such taxable year. To the extent provided in regulations prescribed by the Secretary, such term also includes, for any taxable year— (i) an individual who would be a self-employed individual within the meaning of the preceding sentence but for the fact that the trade or business carried on by such individual did not have net profits for the taxable year, and (ii) an individual who has been a self-employed individual within the meaning of the preceding sentence for any prior taxable year.
I.R.C. (26 U.S.C.) § 401(c)(1)(B) http://uscode.house.gov/view.xhtml?req=(title:26%20section:401%20edition:prelim)%20OR%20(granuleid:USC-prelim-title26-section401)&f=treesort&edition=prelim&num=0&jumpTo=true.
A regulation the statute calls for, and delegates to, provides:
For purposes of section 401, a self-employed individual who receives earned income from an employer during a taxable year of such employer beginning after December 31, 1962, shall be considered an employee of such employer for such taxable year. Moreover, such an individual will be considered an employee for a taxable year if he would otherwise be treated as an employee but for the fact that the employer did not have net profits for that taxable year. . . . .
26 C.F.R. § 1.401-10(b)(1) https://www.ecfr.gov/current/title-26/chapter-I/subchapter-A/part-1/subject-group-ECFR6f8c3724b50e44d/section-1.401-10#p-1.401-10(b)(1).
If the self-employed business has not ended and the self-employed individual remains available to perform services if her deemed employer gets an engagement, the individual might not have severed from service.
If that’s the administrator’s interpretation of the plan’s governing documents, the self-employed individual and her deemed employer might be careful to file tax returns so they’re consistent with not having closed the business. For example, a sole proprietor’s Schedule C might show a zero revenue, a little expense (for a business-privilege tax, or something else needed to keep the business available), and a slight loss.