Calculating form fields

Hi Everyone,

I am trying to calculate some form fields but when I change the figures in the fields it does not update the amounts in the form. I inserted three snapshots for you guys so you have an idea of what I am talking about. I checked the setup of the fields numerous times and they are correct.

In order to have the correct calculation in the third snapshot, I actually had to clear the preparation @ 50% field in the second snapshot.

Thank you for your assistance