For words that only have 3 letters, there's no 4th letter. Such as with the word “increase”, there won't be any more letters Later on and therefore has to be the word "include". The word “addict” is from the BIP39 wordlist however, you might have utilized “addi” for “addict”. You https://thebookmarkplaza.com/story18955804/getting-my-bip39-words-to-numbers-to-work