Maximum stack penalty / movement

[Rysyonok]

What is the maximum stack penalty when it comes to movement? I noticed that larger stacks will take longer to move as opposed to them being broken into several smaller ones - the larger stacks were as much as 50% slower, even if there is no Command Penalty present.

There is nothing in the manual about this - but one of the tooltips in game settings does mention them (AI difficulty) - what are the settings and triggers involved?

[SEPRUS]

The maximum penalty is 35%, it happens if you have a command penalty or if you are not activated (for the move penalty in this later case). If the big stack is even slower than that, then it can be because you are moving around very slow units or a leader is not competent & has a 'slower' ability.

[ERISS]

The maximum penalty is 35%, big stack

With some set option, this max penalty can be less for the AI (if I understood well).