For words that only have 3 letters, there's no 4th letter. For instance with the word “increase”, there aren't any much more letters Later on and thus needs to be the word "increase". The word “addict” is during the BIP39 wordlist however you would have utilised “addi” for “addict”. Shop https://tripsbookmarks.com/story18996139/new-step-by-step-map-for-ledger-seed-phrase-bip39