How do I protect excel formulas in smartforms business calculations

Summary:

I have smartforms that the department or location manager open to input for their budgets and forecasts. We use business calculations becuase the end users can see the formulas and understand how the calcs are being made. We need to protect the formula cells with formatting so that they will not be accidentally overwitten. I have tried using custom styles and it will not take. Is there a specific order of operations that I am missing?

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