No...I think you're taking the rules too literally. They're not meant to reflect "one" or "several" torps (or phaser salvos, or whatever), but a more abstract "combat value".
The CODA starship combat is meant to be abstract, in order to speed up play. I guess if you wanted to really explain why there's no difference, you could argue that firing a single torp is going to cause less damage, but more likely to hit since it's easier to target. A salvo, conversely, will create more hits, but there's more likely to be near-misses, glancing shots on shields, etc.
It's a bit like the old "attacks per round" in pre-3rd Ed D&D - each round was one minute long, and "one attack" actually meant "a series of feints, parries, ripostes, shield bashes, dives, dodges and rolls - which at some stage could do damage."
Same thing for CODA combat - it's very abstract; which I personally like, but then plenty of others prefer Spacedock's nitpicking complexity. I don't mean that in any negative way at all, by the way - I think Spacedock is one of the most sensational supplements for any Trek game, and I still use it to design ships, and then convert them into CODA (I find the CODA design system to clunky, but the combat system is terrific).
Hope this helps some...
When you are dead, you don't know that you are dead. It is difficult only for others.
It's the same when you are stupid...