DodoMaster102, that's very true. Wow it must have been pretty interesting to have huge dinosaurs like that! ?? The bigger and more powerful an apex predator is, the more it doesn't need to hunt in packs. Although, some of allosaurus's prey was also much bigger than most modern day prey too, so it's probably all relative. I think you're right though, it would probably just depend on what kind of prey it was hunting (and maybe also the environment or season).
When it went after smaller prey, it probably didn't need to hunt in packs, but if it hunted larger prey (like sauropods) or faster prey, it might still have chosen to hunt in packs for a better advantage, so who knows? Even today there are some top apex predators that always hunt alone, others that only sometimes hunt in packs, and others that always hunt in packs.