Paraphrasing dev chats;
100 is the top percentile
0 is the bottom percentile.
HBD is modelled, statistically anyway, towards real life.
Thus, a 0 meeting average random factors should hit a HR once every 2500 AB. Any more, and it defies the statistical reality (as noted in BB reference).
We've all seen it. Dude dives for a ball and misses it and has no back up. Noodle bat hits a high pop up in Candlestick and it gets carried out by the wind. Dude bounces one off of Canseco's head.
Don't get me wrong, it's not a waaaay up there important. But the equivalent to "0 maybe hits a HR every 1,000,000 AB" is "100 hits a HR every 3 AB"
It's just as wild an aberation from the extreme norm.