We just took over administration of a company with a cross-tested mppp and a
401(k) plan with a match. The mppp formula is 13.333% for owners and spouses and 6.666% for all others. Upon revieving the prior year allocations, we find that last year one owner received 10.59% and the other received 11.23%. The dollar amounts were the same. It looks like the mppp contribution is backed into after maxing out the 401(k) deferrals and match.

Is this permitted? I would think that the mppp formula was satisfied first, then the 401(k) "backed in to" with possible refunds for excess contributions in excess of $30,000. Any thoughts?

my first thought would be to check the document. quite often they specify that deferrals get refunded first if an ee hits the 415 limit.

I agree with Tom. The documents should specify which plan, and then which money type has priority. Some plans will refund the deferrals first, some will limit the employer contribution. Unfortunately, some point to each other, or each to itself, in which case I'd be inclined to give priority to the one subject to minimum funding (MP), (then fix the discrepancy).