Is there any point to researched AA past Level 3?

[Mithrilotter]

There is good value for researching AA through Level 2 for most units. Level 3 is useful for AA guns and certain critical hexes. Level 3 AA is therefore good for Germany, Japan, China and the Soviet Union.

But I don't see the value in researching Level 4 and above for upgrading critical hexes only. It's more useful to research other important techs with limited MPP's. Some research is capped at Levels 1 or 2. Wouldn't it be better to just cap AA at Level 3 for all games?

[Umeu]

It’s still useful, but only for Axis in late game, to upgrade your cities with level 4 and level 5 AA to at least wound the allied lvl 5 (strategic) bomber madness.

[ThunderLizard11]

I'm not sure - I think someone ran the numbers and said it wasn't worthwhile against strat bombers.