Impossible to judge accuracy of information without some indication of its source. (See Edit)
Plus, I also have to view the accuracy of the percentages with some suspicion when they can't even get Wild Mary's name right.
Given that, if the figures for Witch Tower drops from that list is right then whoever at BB decided that RB should have a higher chance of dropping a WT than DB needs their coffee spiked with something that might actually wake them up to the point they can think sensibly!
EDIT: Apologies.... I didn't explore your second link fully at first. I see now the source of that table is a fan site.
As the thread you link states, "Still, as always with any numbers and new info, grain of salt until gameplay confirms.", and the kind of percentages we are talking about for drops of items like the Witch Tower really do require a massive sample size for any level of accuracy (short of BB actually officially releasing the information, of course).