414s fails in a SHM plan

There are some threads here that come near this, but I can't find anything that really gets to this situation... especially with a safe harbor plan.

Plan excludes commissions from the definition of compensation for all sources - deferral, safe harbor match (deposited per payroll with no true up in the AA), and profit sharing.  For the first several years of the plan, the owner and child have had 50%+ of their total compensation paid as commissions, so 414s would always pass as most NHCEs have commissions of 10%-20% of total comp.

Until now; in 2024, child is not paid at all, and owner restructured so that all his compensation was regular wages.  Sure, I can point to the caveat in my letter each year that this is a terrible idea and only is valid due to the large percentage of commissions that owner & child take, and let us know if that changes... but now that it fails, what actually happens?

There's no PS for 2024, so that's fine.

There's no ADP test, so is there no effect on the deferrals?  Plan sponsor insists that all participants understand that there will be no deferrals on commissions.

For the SHM, I presume that I have to calculate it on an annual basis including all compensation.  But here's the thing: that might end up lowering the deferral percentage and therefore the match (example: deferring $2,500 on $50,000 elig comp yields 5% and you get the maximum match; now if we compare $2,500 to $83,000 total comp, that's 3% and you get a lower SHM).

What's the right way to proceed with this?  Thanks.

Perhaps suggest a solution to the IRS under Rev Proc 2021-30, with a VCP filing? Maybe start with a suggestion that the deferral percent using the comp without commission would be the deferral percent to apply to the definition of comp that does satisfy 414(s) for purposes of calculating the safe harbor match and, if the employer is willing to do that, under VCP you find out if the IRS agrees. Maybe the IRS won’t require QNECs for the deferrals as well. 

We're still discussing how to fix 2024, but now I'm looking ahead to 2025...

Employees get two paychecks per month: one of regular salary, and one commission.  Can we write a deferral election form to specifically say that "I elect to defer X from my salary compensation and Y from my commission compensation"?  I'm guessing that the document can't actually say Y=zero because that's really just an exclusion.  But I'm thinking if the participants choose it (without being coerced or pressured, of course), then we can amend the comp exclusion out, and it's just the per payroll SHM on the deferrals from salary compensation.

I acknowledge that this is kind of shady, and that an IRS agent might not love it under audit, but I'm thinking it's defensible (if the plan sponsor really wants to be that aggressive).

How out of line is this thinking?