For purposes of the war recap that I prepare, a “Yes” under the “At War Cap” means an alliance’s war score going into the war is within 1,000 points of their highest war score over the prior 10 wars.
More accurately, if an alliance wins a war and its war score doesn’t significantly increase from what their war score was before the win, then the alliance is currently at its maximum war score (i.e., war cap). Until that happens, you can’t be 100% positive that an alliance is at its cap.
So for practical purposes, I’m using a bit of a shortcut to allow me to more easily make the determination using formulas.
For top alliances, the increase or decrease in their war score from one war to the next is about 2,400 points (30 team alliances), unless the alliance’s last war was a win at their cap (then minimal change).
Why does knowing if an alliance is fighting at their war cap matter? An alliance fighting at its war cap is either fighting an opponent that is equally strong or that is much stronger. It won’t be an easy war.
An alliance not fighting at its war cap mostly likely has a weaker opponent or an opponent that’s about equal in strength. While it’s possible that an alliance not fighting at its war cap is fighting a much stronger alliance, that’s a much less likely scenario.
This is all from the perspective of 30/30 wars at the Top 100 level and only after extensive data gathering. It becomes much harder to know where alliances outside the Top 100 stand in respect to their own max war score, much less how they stack up against their opponent.