For what it's worth:
We distinguish between the decision height (ADH) and the committal height (ACH). ACH being the absolute minimum considered possible to achieve a safe asymmetric go-around and ADH being some factor added to ACH allowing for pilot ability etc etc. Making the decision at ADH allows some descent while aircraft configuration changes are made. In some cases ACH and ADH may be the same. We use 200' AGL for ACH and min 100' AGL added to this for training; (typically 200' with demonstrated student ability).
What instructors impress upon students is not necessarily what they take with them on their own operations, no matter how clear you think you were. There will always be students who consider themselves as good as or better than their instructor. Does this mean that you failed in your teaching? (This is not to say we shouldn't take any responsibility at all during teaching).
Lastly, in all the talk about IMC asymmetric go-arounds no one has yet mentioned the MAP climb gradient - 2.5%. Last time I checked most light piston twins would be struggling to achieve this at anywhere near MCTOW. This surely would necessitate a higher MDA/DA and an allowance on this height to ensure you were climbing by the new ADH/DA?
AML