I might have used the wrong term “stacked” foundations in the past. English is not my first language, i was referring to foundations that are placed on top of each other, not stacked inside of each other.
So, when you build a foundation on top of another it can’t be rotated in every direction. Only in two opposite directions, and this makes upgrading the bases very difficult if you haven’t placed the foundations in the same direction from the start. This issue wasn’t around until a few chapters ago, so why the change?