The ad for his particular tape says it takes the entire 5' roll to hold up 30 lbs max (20 lbs recommended), so I have to wonder if maybe it isn't the strongest version of the tape.
I've never been able to find true specifications for any 3M tape on the 3M website as all their tape specs are by part number, not retail product names. I prefer knowing the specs by square inch of tape when evaluating applications.