Talk about items.

[the Langolier]

There are 67 base items with the bows being 2x as likely which for the sake of probability

...

Can anyone tell me where I went wrong?

You had me going for a minute. I appreciate your diligence. I programmed that calculator so long ago I went back through the code that calculates the rarity for unique monsters and saw I forgot to include this if statement for unique monsters:

Code:

if (baseEQ[i].iClass == "Bow") //bows have double chance of being picked
            {
                totalBase++;
            }
            totalBase++;

That would count bows twice as expected. But then I checked Jarulf's guide section 3.8.2, which states, "Bows, however, are actually counted twice if the item is dropped by a normal (non unique or special) monster, and thus have a double chance of being created."

So, bows are not counted twice for unique monsters, meaning the total number of available base items are 76.