Based data structure template

I need some clarification, please.
I have followed some threads that discuss using a data structure for as a
template and using the BASED() keyword.  According to what I understand I
read, the data structure is supposed to occupy no storage.  

I have done something I believe is similar to examples I have seen.
However, I do not see any difference in the program object size (verses not
using the BASED() keyword).  In the examples I have seen I see no reference
to using the BASED() data structure at the global definition level (which is
what I am doing).  

Example Line:
     D TYPES_DS      E DS                  EXTNAME(POSREFPF) BASED(TYPE_DEF)

I am using this to define other program work fields and prototype parameter
definitions using my common base definitions from my reference file.  This
way I do not have to rely on a file being defined just to base a work field
like a database field. 

Example Lines:
     D                 DS                  INZ
     D BOTID                               LIKE(@POSID)
     D BOTVER                              LIKE(@POSVER)
     D TOPID                               LIKE(@POSID)
     D TOPVER                              LIKE(@POSVER)


Now, I followed the same example Barbara Morris gave in post
"http://archive.midrange.com/rpg400-l/200311/msg00435.html";.  What she said
was what I saw (the object description size did remain the same, however).
However, the example was only in a sub-procedure.  If I modify the example
to be a main procedure the size does not change between using BASED() and
non-BASED() data structure (as per described in above post).  

So, my question is how do I tell that the BASED() data structure is not
actually using any storage when defined at the main procedure level?  I need
to prove to others that adding the BASED() keyword will not add overhead and
code complexity.  


Thank you,
Matt Tyler
WinCo Foods, Inc
mattt@xxxxxxxxxxxxxx


References:
http://archive.midrange.com/rpg400-l/200502/msg00208.html
http://archive.midrange.com/rpg400-l/200311/msg00435.html