Auto fights - split vs single army performance?

[Banangroda]

Do you get worse performance with auto battles when you use split armies instead of a single army? There seems to be a slight drop for me but I'm not sure.

[feelotraveller]

Yes, I think so.

From observation (of casualties taken) it appears that the reinforcements take time to join battle. (Meaning the opening moments of the battle take place between the unreinforced armies.) The effect is usually quite slight.