Agree that a calendar year 2020 plan for B (e.g., effective 1/1/2020) would require aggregation of A and B's plans for coverage and non-discrimination testing. Agree that an effective date of 10/1/2020 for plan B would not result in aggregation. As far as 1.401(a)(4)-5 timing issues, a 10/1/2020 effective date for plan B, when A and B are no longer part of the same CG should not cause a problem, assuming that the sale to the PE is a legitimate business transaction (i.e., not a subterfuge to avoid 401(a)(4)).