1) Airlading officer arrive earlier than Pg check the numbers
2) A CQC walking up to a long range units is quite different than QCQ walking up to mid to close unit and wining.
3) Even in your own description you described a scenario where assault officer ambush the enemy unit and not just walk up to it.
I suggest you test the unit in game to see how powerful it is.
1. I said "close to", not "identical".
2. I was giving an example of more expensive unit win outright event in unfavorable conditions. My point is, assault officer is a more expensive unit compare to stum, so he should have better chance event in some unfavourable case, to win. However, you didn't describe clearly the situations, like, if both was in the open, officer close in and win with 1/2 models then i think it is acceptable, but if stum was in green cover, officer close in and win with 3 models left then it is indeed too much.
I did test the unit in AI custom, and i didn't deny the fact that it is strong.
What i didn't do is test in vacum.