If those are the rules, then something strange happened to me:
I encountered groups of 10+ Gibberlings and two Dread Wolves on the first map E of Candlekeep, with a L1 character. I have also been ambushed by about 10 bandits with a L2 character between the Map N of Beregost and the Friendly Arm Inn.
Apart from that, the frequent appearance of 10+ low level enemies regardless of party level is quite annoying. For instance, with a L6 or L7 party, I met two groups of 10+ Gibberlings, killed them, spent about 30 seconds away from that spawn point, came back and found another two groups of 10+ Gibberlings waiting right on the not yet decayed corpses of the previous ones. IIRC, that was on the map far E of Nashkel or E of Nashkel. In the original BG1 I also met the same types occasionally, but neither were groups that size encountered quite as often, nor was it always Gibberlings, Xvarts or Tasloi. You know, I like the occasional Fireball-fodder, but this is too much. It's getting boring. Give me a few tougher enemies, please. I never meet 10 Dread Wolves, for instance, although I think a L7 party with good equipment can handle them easily.