If we're going to go down that road, we might as well back up to "is this actually a plan adopted by the partnership," because that question is also hanging out there, and it's entirely believable to me that the partnership's accounting firm could have erroneously told a partner they could make $67,500 of total contributions in the absence of a partnership-adopted plan.

Assuming the $67,500 of contributions are permissible, Lacerte (and therefore ProConnect) supports that much in deduction.