Thanks Molon, that's what I was going to say as well.
Although, the AI sensor performance increases are in some cases pretty dramatic, but that only allows the subs to perform their mostly stock behaviors when they detect another platform. Previously, it was easier to force AI behavior because most of them were just moving targets, running along happily in a world with no other contacts, since their sonars couldn't detect even the loudest contacts past 5nm or so and they practically had to run over submarines to detect them unless they were cavitating.