i used this app for over a year and it was very good, and so were the developers in listening to people and making improvements. however, not so anymore!
this new upgrade (vs 4.1) is very innacurate and they dont seem to care (ive notified them 3 times before placing this review). it seems they are busy with their mirror app "ovulator" (in an attempt maybe to force people into spending another 5 bucks).
in any case, im done. today i purchased another developers app which has a way better user interface (looks much nicer), accurate data (important), much higher rating, and bonus: it is way cheaper.
so id hold off if i was you, at least until the people that will be patient enough to stick with this app give it an improved rating.
otherwise do as i did... look elsewhere.