As part of a Couch to 5K group I’ve seen a lot of results from iPhone and Android users. The iPhone stats are always incorrect.
In the early weeks, the iPhone version seemed to count the walking intervals (ie. not the 5 minutes at the start & end) as part of the running distance. The Android app did not.
Tonight, on week 5 day 3 (5 min. walk/20 min. run/5 min. walk):
The Android app correctly recorded 10 minutes of walking & 20 minutes of running.
The iPhone app recorded 5 minutes of walking and 25 minutes of running!
Let me know if you’d like some screenshots - I can currently get anything up to the end of week 5.