I am calculating the maximum deduction for a client that has a standalone 401(k)( no match) with an employer profit sharing component. And they have a 125 POP Plan.

Three HCEs, who are more than 2% owners are contributing to the premium only plan. Since they are 2% owners, their contributions are NOT deductible.

When calculating the max 15%, do I take gross W-2 less all 401(k) contributions less only the non-owners contributions to the 125 plan, or must I also subtract the owners non-deductible 125 plan contributions then apply the 15%, then subtract the K contributions less the 125 contributions, and the diference is the amount they can contribute to the profit sharing component?????