Dash Trash.
You said:
I never ( and I think it was ops manual) failed engines below 300ft after take-off. I personally used the mixture control based on recomendations from Lycoming and info from the key reprints articles
Well done. Now lets examine carefully exactly what Lycoming said in their magazine Key reprints as to the why's and wherefores of throttle versus mixture. Page 50 states among other things:
"Many flight instructors down through the years used the technique of abruptly cutting an engine with a multiengine candidate to test his emotional reaction (??is the instructor a qualified psychologist - I think not) and judgement with this extreme technique. Big radial piston engines with short stubby crankshafts could tolerate this abrupt (throttle) technique. However, flat opposed piston engines with their long crankshafts and attached counterweights could not as readily take the abuse of suddenly snapping a throttle shut, particularly at take off or climb power. Use of the latter technique would tend to detune crankshaft counterweights and could possibly result in a nasty engine failure.
Since it was common technique by flight instructors to terminate power abruptly to simulate engine power loss, we had to protect the engine. As a result we published in our Engine Operators Manual and in Service Bulletin No. 245, the recommendation that if the power was abruptly terminated it must be accomplished with the mixture control. Of course, this was intended for higher altitude where a complete engine shut down could be conducted safely. However, any practice of simulated engine-out condition at low altitude should be best accomplished by a slow retardation of the throttle in accordance with the NTSB recommendation."
So this suggests that the abrupt ripping back of a throttle was likely to cause engine problems. A slow throttle closure will not cause engine problems and has the added advantage of instant power available if mishandling occurs by either pilot. The mixture cuts were there to stop ham fisted instructors from stuffing the engines by abrupt throttle handling. That was the reason that Lycoming said mixture cuts were better for the engine.
As Lycoming said - "We had to protect the engines" (from ham fisted instructors)
And as for instructors testing the emotional reaction of candidates - surely that is a job for professional psychologists - not enthusiastic amateurs?