coverage and two plans

[Guest cxs]

Employer has three plans; a frozen DB plan, a safe harbor 401(k) Plan only for participants eligible for the DB Plan, and a 401(k) for everyone else. The safe harbor plan has a 3% non-elective contribution, the non-safe harbor has an employer match.

I assume I would do separate coverage tests for each of the 401(k) Plans treating the participants eligible for the other plan as not benefitting under the Plan I am testing. If they fail the ratio percentage test I could do an average benefit test and would need to test all three plans together. If they failed coverage an employee might get both an employer match under the non-safe harbor plan and an employer non-elective under the safe harbor plan. Is this correct? Would it make any difference if the match was a safe harbor match?

Thanks!