Yes, this can be frustrating.
When opening Blender, the default cube loads.
Then set units to meters, and you get a 2, by2, by2, meter cube.
Then set dimensions to 1, by1,by1 meter.
That is .05 in all directions of the default cube. LOL.
Then reset XYZ Euler to 1 all, and the cube changes again... LOL.