Do a shotgun hollow point cause more damage then the average shotgun slug?
Yes. Getting shot COM with a hollow point slug will kill you 99.99% of the time, instead of 99.9% of the time.
Brings up an interesting question, I once asked some LEO and medical (SF medics) friends why I had trouble finding survival stats on COM hits with slugs...they laughed...turns out the one-shot stop stats and lethality stats for center of mass hits with slugs (when in range say less than 50 yds for slugs) are pretty uniform at basically 100% for unarmored targets.
That being said, it is still shot placement that matters.
Close range (10-15yds) with 00 buck is also pretty invariably lethal without armor--similar I would guess to 7-10 hits COM with a pistol...freak occurrences notwithstanding.
Also interesting when I started looking into it is how different the survivability stats were between rifles and pistols for COM hits without armor, brings new feelings about the "use the pistol to get to the rifle" thoughts.
So with that, shot placement is still king...mis-aimed buckshot is still mis-aimed, but if you are on target, nothing beats a shotgun at close range or a rifle at any range in terms of stopping power.