I took the index from the words, transformed the number to binary, additional a few zeros, calculated the sha256 digest, took the primary part of the hexadecimal to transform it to binary, additional three zeros to your 8 digits with the binary and got 00000010011 which interprets to 19 in https://bookmarkblast.com/story19070909/getting-my-bip39-words-to-numbers-to-work