At 400 feet?I guess you was lucky not to encounter any aircraft during your flight.
You know, the "reducing power to motors" thing is just an informational message to you. That doesn't mean stop flying, it just means that it's reducing power to save the battery. In fact, the message should give you confidence to keep pushing it against the wind, because it's got your back. If RTH worked, then it was doing the same thing, just slower.