Rashid Bhai you're a retired Naval Officer and
@Neptune was training to be a Naval Officer so I don't know much in front of you guys but to me it seemed that successfully operating a Sub in War, even if it were an older platform, must've accrued some invaluable experience to the Pakistan Navy that should give it an edge when compared with other navies even if they operate a newer class of submarine ! And its not as if the learning stopped - Surely the experience gained from operating the Trench Class in '65 and '71 would've followed through when we got the Agostas; perhaps even develop Subwarefare tactics that were intensely Pakistani in their design.
A little like how our boys in the Airforce have acquitted themselves very well when training with foreign air forces even when they're flying relatively older technologies like the F-7s or the Mirages !