It was on a dedicated server.
Also, that's not exactly correct from what I can tell, but I understand what you're saying. It was never really meant for MP, but it does work with it quite well regardless. It seems to be a hit and miss for some servers from what I've heard, though I've had no problem with it personally. Only some of the features don't work, such as surrendering or enhanced hearing which I don't mind, though the basic elements seem to work just as well as it does in single player. Heck, I personally prefer bCombat, even in multiplayer, over that of ASR AI, since the former does a better job of handling cover than the other and is far more aggressive. Just to note, I don't have any optimization issues with it either online. The only big FPS drain, especially during combat, that I've discovered over hours of testing is this particular mod. :(
Keep in mind that I found that this mod causes huge frame drops in both MP and SP. It's not always consistent either, since it may happen during a small firefight or not. It does seem to happen more frequently in large ones, of course.