Self-employed

I am an employee who has a t2200 form. I am using TurboTax online and I am trying to understand where I need to put the information of my expenses. There are 2 sections where you can add the expenses of the house and the expenses of the section I use as an office. 

 

I added the information in both sections but it looks like the amount due is getting reduce twice. So I assume that I am doing something wrong,