DSLR focus or images plus both have a focusing section in each program.
It does this by downloading images to your PC but the difference you say is it gives stats that you cant see by eye to fine tune focus.
Well worth the money both these programs.
I would be checking if the 400 is supported in both these programs first.
http://www.mlunsold.com/
http://www.dslrfocus.com/