You can't input the inverse directly into the ref, you need to multiple the old ref matrix witht the inverse and use the resulting one for the ref line.
[200 100 50 1 0 0 0 -1 0 0 0 1] * [200 -100 50 -1 0 0 0 1 0 0 0] = [0 0 0 1 0 0 0 1 0 0 0 1]
But I don't understand why you making it this complicated, especially since the inline model doesn't use a 'nice' center point. It's much more easy to just use copy and paste in LDCad or MLCad to create a submodel using a decent center (e.g. the chair at 0,0,0)
[200 100 50 1 0 0 0 -1 0 0 0 1] * [200 -100 50 -1 0 0 0 1 0 0 0] = [0 0 0 1 0 0 0 1 0 0 0 1]
But I don't understand why you making it this complicated, especially since the inline model doesn't use a 'nice' center point. It's much more easy to just use copy and paste in LDCad or MLCad to create a submodel using a decent center (e.g. the chair at 0,0,0)