No good to me. There's no allowance for bakery stops!! FWIW there is an app version of Open Office. Look in the Play Store for AndrOpen.

It looks intriguingly useful, but I notice that it does not take into account the front and rear axle limitations of the towing vehicle. This is a critical measurement that I have found with my rig. I can be well within the maximum GCM, GVM, and towball mass, but exceed the rear axle mass by not distributing the load properly inside the car, i.e. less weight in the boot by moving heavy tools into the footwell of the second row seats to shift some load off the rear axle to the front axle. I generally check the three axle weights (2 x car and 1 x caravan) by using the various free weighbridges (in Victoria). Tow ball weight is checked at home with a short timber beam and bathroom scales in a 1:2 proportion. Attached picture shows the setup.