There appear to be two choices with aircraft AI, high level "toss" bombing that is always inaccurate, or the dive approach to low-level. Personally I am of the opposite opinion, that to see a Sunderland toss bomb from 1000m and splatter depth charges in a loose scatter hundreds of meters from the U-boat is more unrealistic than supposing it can dive and deliver a more accurate attack.
The Liberator is more confusing as it appears more like a high level bomber in game, instead of something more relevant to a subsim like the VLR patrol planes that closed the Greenland gap and accounted for many U-boat sinkings. The devs gave it high-level AI, green skin, and no depth charges, I reversed that cause when I sail into the atlantic I am not a target the size of a German city or an oil refinary.
Anyway, those who want to change them for whatever reasons now know how.