As for materials, for a theoretical 2 story 20Wx50Lx20H home (2000 ft^2), you have 1,000 ft^2 of roof (assuming flat) and floor, as well as 20,000 ft^2 of wall.
Cheap fiberglass insulation is $1.32 per ft^2 10 in thick (1/10/24) https://www.homedepot.com/p/Owens-Corning-R-30-Faced-Fibergl...
Assuming we use this for everything that is $29K
I'm going to pull some ratios roughly out of this article.
https://www.greenbuildingadvisor.com/article/how-much-insula...
This is in the high energy efficiency area of construction but I'm using this to illustrate the inefficiency of a standard floor/wall/roof thickness, take it with these caveats.
So if you were building to this insulation cost would be:
1,0001.32 + 20,0001.32(2/3) + 1,0001.32*(1/6) = $19K
You could view that as $10K of wasted material or, if you chose not to fill the blocks with full thickness material, calculate how much of their volume is being wasted to achieve a standardized thickness. Lots of ways to look at it but, to put it simply, I think however you look at it, it's not optimal to be unable to adjust your floor/wall/roof thickness.
