[Thor]

There's some random factors when fighting, don't forget and as people levels and train stats, the random gets "larger and larger".

Maybe you're comparing your best "leave" fight ever with your worst "zerk", who knows?

I got fights where I lost with zerk but won with leave vs the same guy on the same day, it's part of the game.

If you're lvl 5 with all lvl 5 stats, you know you will win vs a lvl 2 with all lvl 1 stats but when we're talking lvl 30-40-50 with stats up to 60-65, that's some huge room for randomness.

Plus, if you have 30 of all stats and he has 50+, no bonus will help you much either.