Ok. After a few test I've made the following experience:

It works nicely and it's defintely usable on the field.

But I can't enter 0.06 as CoC, this is the value for 6x7 medium format film. Neither by typing nor by pressing +/-.
I do miss f/11 to f/32 which are quite important for medium format.

I'd really love to see an interface like the android version here , since I'm working with different cameras all the time: http://dofmaster.com/android.html

I'm willing to donate 20$ by paypal for such an app for the N900.

Again thank you for your work.
Best,
Alex