I am a Missouri resident and purchased a new vehicle in 2017. I entered the state and local sales tax that I paid in order to register the vehicle in the 'vehicle registration fees' deduction field of the software. 

It is my understanding that you can only use this as a federal deduction if you do NOT use your state income tax as a deduction. In my case the state income tax that I paid exceeds the state and local sales tax paid to register the vehicle so I would think that the registration fee would not be used as a deduction. However, in my deduction summary, both the registration fee and the state income taxes I paid are listed as deductions. 

Am I missing something? I thought you could only claim one or the other.