Makes perfect sense now, thanks to the explanation!
I tweaked my design a bit to get it within one third of a cubic inch (Close enough!) of your original design. 😉
It’s not quite a perfect cube anymore, but now I only have three table saw fence setups I have to do.
Two for cutting the six panels to size and one setup for the rabbets.
Let me know if you would like me to share the SketchUp files. Note, I don’t use “SketchUp for Web”, I am still using the old 2016 version. :/