Another point to bear in mind is the surprise factor. When it is being practised as an excercise, you set up the aeroplane in climb-out configuration, settle yourself down, then 1 - 2 - 3 GO!; power off, nose down to the right speed, wind on the bank, pull to the nibble, reverse the turn, roll erect (don't forget a simple 180 isn't enough - to regain the centreline you need to do a tad more than a 180, then reverse the turn).
If it happens for real, the chances are you will lose vital seconds before you realise *yes - it has actually happened*, by which time the speed will have bled off a bit so you'll have to stuff the nose down smartly.
Result? - If it happens for real, you'll likey have less time, and less height to play with than you did when practicing. That 400 feet could easily become 600 feet or more.
But it's an interesting one. Must give it a go and see how the Chippy performs it.
SSD