Just info.
Think in your own way and your own point of view about this WIF range
Do we have GPU crackers for WIF Private Keys? or do we have someone that can build 1? these have more potentials for brute forcing puzzle 66 from the Random Point of view for probably the last 16 - 18 characters ranges scanned sequentially, compared to the hexadecimal private keys because of the checksum involved in the WIF Private keys... this might be it, every hexadecimal key is valid but not all WIFs are which brings us to the point where scanning might be fun to play with
What is the point of this if what you see in every row is just representation of padded zeros?