When does a country "prepare for war?"

[ForzaA]

I know it means they'll join the war on the next turn for "their side", but at what mobilisation level is this triggered?

Closest I can find that could possibly explain it in the manual is;

Impending War Entry
Once a country’s Mobilization Value reaches 90% there is a random
automatic boost of 1-5% per turn, and this will continue until the
Mobilization Value reaches 100%.

But I don't think it is that? Or is it that and the level got changed?


Context: in my current MP game, the USSR "prepared for war" at the end of my turn as Axis, at least a turn ahead of my expectation.
Now the USA is doing the same..
So either I don't quite have the cutoffs quite right OR there is something happening that I'm not aware of.

Mind, even without it, my situation was pretty much hopeless anyway (my opponent succesfully threw everything at France, holding me there until mid-late 1941 - but then it's the little things that REALLY throw you off.

[ThunderLizard11]

I always though it was 96-98% but would need to pay closer attention next game.

[BillRunacre]

90% is the trigger.