Allied subs and Japanese Barges

[Kingfisher]

Question - when attacking a target does the computer recognize the difference in target size, or does it see every target as one size and thus apply the same amount of firepower?

Why I ask is because more than once I've witnessed allied subs using torps against Japanese barges. According to the game's database the largest Japanese barge is the 17m Daihatsu, coming in at a whopping 35 tons. Yet in a current game I watched an old S-boat pump enough firepower (3 torps and 12+ gun rounds) to sink a CA.

[xj900uk]

Best to be sure,  just in case...
 
BTW,  can you imagine an S-boat fighting it out on the surface with it's pop-gun against a heavy cruiser irrespective of whether it had just torpedoed it or not?

[ILCK]

I'm constantly seeing my subs getting into surface gun battles with AP's they torpedoed and, apparently, surfaced to duel with out of some sense of chivalry.