It was developed by three organizations - hence the confusing designation. It looks like this There are two accepted methods for sizing masonry walls. Rational - A scientific engineering analysis performed by a structural engineer which involves examining the loads acting on the wall and comparing those actual loads to allowable loads which are defined by the strength and orientation of the materials involved. Chapter nine of the MSJC code establishes several simple formulas that enable one to size walls without an in depth analysis.
Empirical design is a reliable and acceptable way to build efficient masonry structures.
I wonder if anyone will use it.