Parametric stackable and stable square box

Yet another scalable box...
I was looking for a simple stable square stackable box.

What I found was either easy to print but very thin wall, or VERY thick walls or difficult for me as a beginner to parametrize. So I decided to train some 3 modelling. How hard can it be :)
Well, .... it took a while and is far from perfect, but worked for me.

The uploaded FreeCAD model has got a width of 90mm and a overall height of 50mm.
You can download the FreeCAD model and open the spreadsheet. There you can adjust width and height of the box as well as the wall thickness.

Default is wall thickness of 1.25 mm which comes out as 3 lines with a 0.4 mm extruder.
To be a bit more stable also 1.65 works very fine for me, resulting in 4 lines wall thickness.

Note, if you change the wall thickness, you may manually need to adjust the parameter of the part 'MiddlePlabeChamfer' to be printer friendly without supports. FreeCAD does not allow parameters here.