Open Source Maintenance Fee for small project

[matejskubic]

I would appreciate some clarification on how the maintenance fee applies in my situation.
I am the only developer contributing to a small project, and the project generates approximately $100 per month. The client company has 5 employees, while my employer has about 100 employees and is wholly owned by a parent company with about 1,000 employees.

Which organization should determine the applicable tier: the client, my employer, or the parent company? I would be comfortable sponsoring VerifyTests at US$5 per month, but arranging the US$20 monthly payment through the company would be disproportionately difficult for such a small project.

Is there a compliant option other than the US$20/month sponsorship, such as using the US$5 tier or agreeing on a private arrangement?

Thank you for any guidance.