Combo DB DC Testing in year of DB Plan Termination

[SCooper]

We have a cash balance plan that set a termination date in September this year. We permissively aggregate the DB and DC plan each year to pass general testing. Does the plan termination date create a short plan year for the DB plan and does that now make the two plans unable to be aggregated due to differing plan years or is amending the plan to terminate 9/30/2023 not creating a short plan year for testing purposes? No assets will be distributed this year and both plans define the limitation year as the plan year.

I don’t believe the regs are concrete on this scenario and that it could be interpreted as being a short plan year. But it could also be interpreted as being a short plan year only during the year when the assets are distributed not necessarily when the plan term date is effective.
 

Secondly If the DC plan is terminated 9/30 as well, I’m thinking it would be reasonable to aggregate them under this scenario?

Thank you!