It was huge back in the 80's with large production builders. I wouldn't loose sleep over it providing that you are realizing part of the savings. It is tough as nails and I've seen modular homes in a traffic mishap during transportation have taken severe "blows" where the trailer's out riggers (these were 13' wide modules) ripped out a half dozen floor joists. The walls were finished and painted and the drywall was still perfect with the exception of a couple of feet at a corner where it would be repaired with a little caulk and paint. (Inside corner had a hairline crack) It was not limited to modular and panellized homes. Andersen windows used to have windows with a reversible nailing flange that would accommodate the 4 1/4" wall thickness.
