Right, I'm trying to say that those two missions didn't make sense in SC, let alone DW.
US submariners don't mind a bit of the daring-do, but we weren't crazy.
Maybe try it in a Virginia class? Its got better sonar and its supposed to work better in shallow water than a 688.
Or, better yet, edit in a DDG as your drive-able platform. Its much better suited for those kinds of missions.
PS- From your last edit: Yes, the DW mission editor has limitations. If the P-3 is tasked with finding and attacking you, that's what it will do.
You could check if you did something that gave your position away (radio mast or scope?) but I also doubt that was the problem.