I'm not sure if Logix Pro has different time bases or not. But RSLogix 500 (What it's modeled after) has a drop down menu on the right hand side of the number where you can choose between 0.01, 0.1, and 1 (I think those are the values).
As far as the 0 value under N7:0, that is the integer value in the N7:0 integer file. To change that, you need to change the value stored in N7:0. You may be able to do this by highlighting the 0, typing in a number, and pressing enter. If not, you will have to open the N7 Data Table and modify the N7:0 value there.
It's been quite a few years since I've used LogixPro, so I cannot tell you the specifics of it, only how it works in RSLogix500, and hope it is close enough.