My subwoofers are about level with my mains.
I used to run them much greater, but later found that what was missing for that impact wasn't bass but rather lower midrange, which comes from your mains. No subwoofer 'punches,' they aren't designed to, the 'punch' is more like 500Hz. So, perhaps in the IMAX the reason you felt the subwoofers were run much higher was simply because the mains were keeping up with the subs. Most home theaters have subwoofers way too powerful to balance with their mains, and so you end up with this drone. Then to compensate, they add more bass, which makes it worse - when the real solution was to get some bigger mains.
The real solution is to level the subwoofers with your mains, and then just turn the volume up. The problem is most mains can't keep up with the subwoofers when their level matched, so people turn the mains down and the subs up...hence the crazy spiral in the wrong direction.
Subwoofers have a job of providing the foundation, but really the lower midrange mixed with the LFE is what makes the explosion sound like your house is going to fall apart.