Oscar is ok. Victor, akula, kilo are really hard to hit. Also I did some more tests over the weekend. Those high end subs are very hard to kill especially when there is a thermo layer. The AIs are very smart in using the layer as cover by going up and down it. Also the seeker's effective range seems to have been reduced as well. If you activate your weapon like 1/2 of the distance, it's very easy to miss. Knowing the exact distance to the target is imperative to achieve a successful kill. Under normal game condition with show truth turned off, ASW becomes a difficult task cuz the actual distance is very hard to determine. Before, I can get by with my soso TMA skill, now under RA, I pretty much have to rely on AI TMA. Before playing US subs, if I can get an ok TMA solution and got the first shot off, I can pretty much hit the target. Now, even with an excellent TMA solution, I have to first use wire guidance to babysit the torp until it's very close to the target (or at least pass the first CM spread) then turn the seeker on. Otherwise, good luck on getting an Akula.
If any of you have issues doing ASW in deep waters with layers using torp either MK48, mk50 or mk54 please let me know. I have worked out a few tactics under show truth environment and tested under normal game conditions with show truth off.