Here is what I've come across in the example file. It turns out Reverse option in MultiplyMeshb operator reverses the way alpha is applied to the multiplied mesh.
Enjoy!

what I found - If you press "O" button in viewport while you on camera, and move around this cubes 360 degrees .y, one side of cubes is transparent and another is flat
If you unchecked reverse button and move again around cubes, then another side of cubes will be transparent.

Yep. That's basically what it does

Ok thanks. intersting, never care about this parameter.
It reverse meshes order.