Singleton Class Creation Differences (rb_singleton_class() & rb_define_class_id() )

While Looking closely at Singleton Creation, it became obvious that 
there are two distinct
Singleton creation patterns.   They  are generated  by the following 
functions:

          1) rb_define_class_id()
          2) rb_singleton_class()

I have included the start and end node charts for both!

The question is why do they inherit differently??   I suspect
it has to do with Special Handling for CLASSES?

I also suspect the difference is subtle and never the less very
important to the operation of RUBY

           Chuck T

Thanks.