A very good reminder that when practicing non normal items near the edge of the envelope that every aircraft is slightly different. We can generalise on normal operations when flying from A to B in light aircraft and apply techniques for normal control that fit across the board. However when dealing with non normal/advanced scenarios it's extremely important to know that aircraft type and its characteristics. The C150 explicitly states to move the control column briskly forward to break the stall, and even then it can take a rotation to come out so needs patience. Then there's issues if you do these things outside the W&B envelope, which both scenarios described in the report are above MTOW, you are into test pilot territory then. This then comes down to how important is spin recovery for the average pilot, the recovery techniques taught are only for the aircraft that it's practiced in. It's much better to teach avoidance of the zone where these problems occur as once you get close to these edges each aircraft will behave differently, even to the point that weight and balance, power, config, rain, ice, insects, damage, etc can all make the aircraft behave differently around the stall.