"Difference" means subtraction. You bid 26 on Nevlas. The current bid was 3. That's a difference of 23, making it the largest difference. Make sense? Here's the log:
Nenette-76 bids 4 on Nevlas, outbidding Guelsson. (The bid was 23 away from Nenette-76's max bid of 26.)
By the time it gets back around to you, that difference is smaller than the difference between Ambas' current bid (0) and your highest Ambas bid (21). You've indicated that you want Ambas so much that it's better for you to get it for zero than to continue bidding on Nevlas, so that's what you do:
Nenette-76 bids 0 on Ambas (and is willing to bid up to 21 if needed)
You don't know the *max* bid of other players, but you don't need to. It's the *current* bid that matters for determining the difference.
I see a lot of complaints that people don't understand the wiki's wording, but no suggestions of better wording. How would you have worded this?