Wait, you had a 172 trimmed for 90Kts. and extended 10* of flaps and it pitched up 35* and stalled? Um, the 172 has a trim change with change in flaps, but I've never experienced anywhere even in the ballpark of 35*, and I've dang sure never had one stall from flap extension, same goes for any of the 8 or so other planes I've flown. My students fail to apply a little forward pressure when they extend flaps all the time, and the plane doesn't even pitch up to the normal climb attitude. I think something was majorly off with your experiment there, but I'm going to try those things out to get my own comparison there.