AI making changes way too late?

Is it just me or do the AI manager make changes way too late? I see them make substitutions whenever, but they never seem to change formation before the 91st or 92nd, or even in the 93rd minute in some cases. You get the "they now appear to operate more defensively" or whatever, but I just played Shakhtar in the Champions League group stages, and they needed one point to advance to the knock-out stages. I was up 2-1 and they still played their starting formation, and only in the 92nd did they actually change to a proper attacking formation.

In my current save, Grimsby changed formation to a 4-3-3 three times but there were no subs and the players seemed to occupy the same positions throughout. That is the only game were I have seen a formation change. probably because I am in the BSP. Still strange though.