Why does dimensions change on models when decoupling from the hierarchy in Outliner.

Sorry if I don’t know the terminology explaining my problem.

The models have been imported from Sketchup as collada.

I need to decouple the “layers” group_2 and group_53.001 and make them into two independent layers and deleting the layers “SketchUp” and “group_1” from the Outliner as shown in the picture below.

When I try to move these two layers out of the hierarchy the two layers dimensions changes.

When zooming far enough out I can see them.

I need the layers to retain their dimensions when decoupling from the hierarchy. Changing the dimensions back to the original size does nothing. How can I do this?

Does the empty the objects are parented to have a scale other then 1 ?
If so apply the scale for the empty (Ctrl+A) before unparentling

Or keep the existing transform when unparenting (Alt+P) https://www.blender.org/manual/editors/3dview/object/relationships/parents.html#remove-relationship-clear-parent