15 days/15 minutes is not a coincidence at all. They were both present in v1.5. For 15 days, usage was unlimited. After day 15, recordings were limited to 15 minutes.
In v1.6, the 15 days was inadvertently removed. This meant that the 15 minute limit was in effect from day 0.
In v1.6, the 15 days was inadvertently removed. This meant that the 15 minute limit was in effect from day 0.