no, you're the one who's wrong. According to the latest mcd script, what I see is that they're scanning everything, leaving the least unlikely places for later. This is mathematically true. In 256, it's unlikely to find 2 "aa"s, so in a 256 block, when they find "aa", they skip the rest of the block and leave it for later. This makes a lot of sense theoretically. However, in practice, both methods work the same, so they're equally efficient. Neither breaks any laws, neither is better.