Yes, for now, we are going with this general scheme, as the signals themselves sometimes have a + or -1 km accuracy. In such cases, any accurate calculations are meaningless. So, we assume a safe conservative value for accuracy, and stamp the Arr/Dep time accordingly.
But yes, sometimes signals are much stronger, and in such cases, we can be more precise with arrival times. This will be refined as the app gets better over time.
Thanks.