Fighting in Poor Lighting

[VariousRen]

A party of PC's is being ambushed at night at their camp, which is lit by a few torches and a camp fire. We've already established that the torches and low burning camp fire give a -3 vision penalty because they are throwing long flickering shadows, so a -3 to all attacks going on unless people have night vision.

My question is what happens with defenses when lighting is used to penalize attacks. Basic Set pg.394 says that all attacks are penalized, not skill, so as written defenses shouldn't change. This seems like it would turn most fights into a stalemate, with evenly matched opponents having normal defenses but no extra skill to deceptive attack it down to hit-able ranges.

I haven't had much experience with low-light fights, so I figured I would ask if this would cause any problems and drag out fights, and if defenses should be penalized by penalty/2.