I think it could work okay if the game scoring is fairly linear, such as on many modern Sterns.

Some game scores, like Fish Tales or Creature, take a giant jump if the player manages to get to super jackpots. The top player's score might by 5 - 10x the next player's because of that.

Personally, I'd never use natural log because any scoring system has to be simple and intuitive for the players. What I might do if ties are a problem is simply use them in just that case. But to me, a simpler method would be to just calculate the median or average, and then compare how players did versus those. So if player 1 performed against the median on four games as follows: +5%, -8%, +20%, +7%, then their overall performance was +23% vs the median. If that's better than someone they tied with, they win the tie-breaker.

It's a common point allocation for Herb-style tournaments, nearly all of which are for IFPA (wppr) points. That's probably where it came from.

One thing I forgot to add is that if time permits and they'll not drag out too long, go ahead and do tie-breakers. Most players I've met would rather their fate be decided via actually playing it out vs a formula. That said, I understand where you're coming from as far as weekday events and wanting to keep the event to a reasonable length. I use a formula for PAGG for that reason.

Always remember that there are a lot of acceptable formats for IFPA that are very time-manageable, such as Pin Golf or time-limited games. I expected a lot of complaining with time-limited formats, but it turns out the players love them.

Another thing is if you use a format with a qual and final, it's likely the 'serious' players will make the final and everyone else will be able to leave at a more reasonable hour. The finalists tend to be more serious players and are willing to stay late for pinball, even if it costs them an hour of sleep.