Not an expert but I assume relevant RL factors in terms of hitting a submerged target or not is the depth the target is in, the relative direction it's going to compared to the ship dropping charges, the relative speed it's going compared to ship dropping charges, and of course the area which the DC or DCs cover.
For every depth, every speed and every bearing there is a mathematical solution to get path of sub and DC to intersect (i.e. you need to make the charge to hit water at a certain point, which takes into account sub speed, bearing, depth and rate of sink for DC). The game is not abstracted to the level where depth, speed and bearing are taken into account, so imo it is impossible to model this level of accuracy and the area which the DCs cover versus the area which the sub is in. After you get those values, you could probably start further developing some statistical model for hits.
The game probably abstracts ASW on a level which takes into account crew experiences, and probably number of ASW weapons, which have certain accuracy and effect/pen values. Then throw in some random multipliers or rolls, and shallow or deep water. AFAIK the game DOES model/have max depth ratings for different subs, which increases the modeling capability.
During the Pacific war, neither Japanese or US subs had very deep diving depths compared to German subs. Some have theorized it's because these subs in the Pacific were larger in volume, meaning the pressure hull had to cover more volume and in order to not make these subs so ridiculously large and heavy and unusable, the thickness was cut down a bit. Another thing if you look at a Balao or VII boat, you notice the VII is much more cylindrical/round, which equals more compressive strength (as is evident by calculated crush depths of 130m vs 230m).
A fair bit of information was provided by the devs regarding ASW. Precise details of course were not provided, but enough information was made public to understand the degree and type of abstraction incorporated into AE. A search of those devs comments will disclose that your post, whilst inaccurate in certain respects, nonetheless is soundly based.
What so many modders seem to refuse to acknowledge and understand is that a high degree of abstraction is unavoidable. Certainly if one is designing a game which can be played on the average consumers hardware, does not get bogged down unnecessarily in petty details which turns playing it into a chore, does not require a PhD in order to play, and can retail at a price point which generates sales and profit generation.