Seems the graph is incorrect because it does not factor in the dust level threshold. Or is dust level going to be abandoned when the new curve is activated?

further, there truly doesn't need to be a steep section to the curve. Try a curve of the shape N x S^log(N) instead.

Here the blue line is a line close to the blue line proposed above. The orange line would be a more fair alternative that pretty much maps to a 17% increase of influence per increase in fish size. Because there are no extra steap or less steep parts in the graph, incentive scales perfectly between all fish sizes, so also there should be no sweet spot for abusers (or bid bot users) to aim for.