solo 401(k) clarification

It's been awhile since I looked at all the rules, but I believe she can only use her W-2 wages from another employer to contribute (elective contribution) via withholding to that EMPLOYER'S 401K plan, NOT her solo

401k. Contributions to her solo plan are in two flavors: 1. There is the elective $17,500 ($23,500 if age 50) based on up to 100% of her net earnings from self-employment and 2. the employer contribution which is "effectively" 20% of her self-employment earnings. Elective contributions are per person not per plan. In other words, the $17,500 is the maximum amount for the year even if she had her own business plan and also a plan through her employer.

E.g., if she had net earnings in her business of $30,000, she could contribute her elective amount of $17,500 to her solo and then make the calculation to compute her employer contribution to the solo (20% of $30K). If she had no net earnings for the year in her business, she could not make any contributions to her solo plan. She could make elective contributions to her other employer's plan via payroll withholding.