how come each puzzle uses a different address index?

puzzle 1: 1436pPYRTYWszXVdQxLdcfNVpMEn3VsZQn mirror play excite proud danger galaxy negative wrong slender merit girl
uses address index 0

puzzle 2: 198UdNZ3NF7gnDQesR2LkeqMVWqz6vqqdv hammer sheriff void deliver drum beef plate grape interest twin side concert
uses address index 9

puzzle 3: 1551aFmwryENPgdFJEDRHurY3Urq1ErTYd roof body island hollow shove ignore crazy teach pigeon cover march ordinary
uses address index 7

so not only do you have to guess the seed words, you have to guess the address index to verify the seed you're testing has a matching address.