I bet the 76% accuracy is coming from the CharaChorder's input method. From its website (https://www.charachorder.com/product-page/charachorder):

> CharaChorder’s internal processor arranges the letters on-screen in real time faster than the human eye can perceive.

So if it inputs one word, deletes it, and writes a new word every time you press a new letter, that would result in some decreased accuracy, even if the user doesn't ever correct anything.