ASG and multiple plan issues

[SRM]

Corporation A sponsors Plan A (a 401(k) PSP). Corporation A is owned by equally by 4 MDs and has other employees. Plan A provides 415 max benefits to the MDs and signicant benefits to employees (assume 10% of comp.).

Corporation B sponsors Plan B (a PSP). Corporation B is owned equally by 2 MDs (2 of the 4 owners of Corp. A) and has no other employees. Plan B provides 415 max benefits to the 2 MDs.

The only overlapping employee/participants are the 2 owner/employees of Corp. B.

Assume that the Plans are operated as if there is NOT an ASG.

If it is later determined that there is an ASG, what are the potential issues and problems facing Plan A?

Clearly, Plan B has coverage, discrimination, and 415 issues.

But, what are the issues facing Plan A?

It seems like Plan A has potential 415 issues. It may be possible to include coordinating language between the plans to indicate that any excess is attributable to Plan B. Additionally, Treas. Reg. §1.415-9(b)(3) indicates that under certain circumstances the employers could determine which plan is disqualified.

Are there any other issues facing Plan A?

Ideally, if it is later determined that there is an ASG and the issues cannot be corrected short of disqualification, the parties involved would like the result to be disqualification of Plan B, but not Plan A (older plan, higher balances, more participants, etc.).

I am not looking for an answer as to whether this is an ASG but instead what will happen if it is determined to be in the future. The advice will be to seek a ruling on ASG status but I am considering the future if that route is not taken.