Ok here is an example. Some dimensions are picking up an exterior dimension which adds undesired width to the wall. I highlighted the ones that are not right.
are You sure ?
what I can see here is correct…
When You stand inside this room and You will measure those yellow marked walls – You will get the same results as on picture.
I just redraw Your room and put those dimensions on.
In this case all items will be inside this area, and they will stick to inner side of it.
When You are measuring wall You measure it as it is (with wall thickness).