His reply looks and sounds like a typical reply from ChatGPT or similar AI chatbots.
It's just he's too lazy to read the entire OP or missed that part to include that there are 30 to 50 words in the list.

That is only true if there are only 12 misarranged words.
Since: 12! = 479001600

But in OP's case, it's (using your suggested "formular");
From (if there are 30 words to choose from): P(30,12)=30!/(30!-12!) or 41430393164160000 permutations
To (if there are 50 words to choose from): P(50,12)=50!/(50!-12!) or 58150627116341760000 permutations