Retirement Savings Contribution Credit

This is the first time my wife and I as married jointly filing tax payers are eligible for this credit. We made around 75k in 2024. Now, I contributed 1700 into a Roth 401k, my wife contributed 1500 into a traditional 401k. Why are we getting 400 back? Wouldnt we get 320 back instead since that is 10 percent of the amount we contributed? Turbotax is automatically allocating 400.00