The calculations are spot on if you input your own weather data. The automated weather finder used to work until last fall and now wont work at all. I emailed the support staff over a month ago and they are aware of it but it doesnt look like they are going to fix it. Six months is plenty of time to fix a small bug in the system. And since incorrect weather data will throw the entire calculation off, its pretty much useless u less you have some other source for weather data.
Now that you have to pay for the app, I wouldnt buy it.
Ukelk about Ballistic: Standard Edition, v6.1.0