Moving SPACES in numerical fields

Hallo,

I have a little question about moving SPACES in numerical fields, maybe 
for beginners, but I  nowhere found a clear answer
:-)
To ilustrate it first here is a little sample:

       IDENTIFICATION DIVISION.
       PROGRAM-ID. RECURTEST.
       ENVIRONMENT DIVISION.
       CONFIGURATION SECTION.
       SOURCE-COMPUTER. IBM-AS400.
       OBJECT-COMPUTER. IBM-AS400.
       SPECIAL-NAMES.
       DATA DIVISION.
       WORKING-STORAGE SECTION.
       01  PSSDPO-RECORD.
           05 PSSDPO-KONTROLOR-GRP.
              10 PSSDPO-KONTROLOR-INPT.
                 15 PSSDPO-KONTROLOR         PIC 9(10).
              10 PSSDPO-KONTROLOR-OUTP REDEFINES
                  PSSDPO-KONTROLOR-INPT.
                 15 PSSDPO-KONTROLOR-EDIT
                                            PIC 9999999999.


       LINKAGE SECTION.
       PROCEDURE DIVISION.
      * Initialize Group-Items
           INITIALIZE PSSDPO-KONTROLOR-GRP.
      * Move SPACE into numeric field
           MOVE SPACE TO PSSDPO-KONTROLOR.
           MOVE SPACE TO PSSDPO-KONTROLOR-EDIT.
      * Move SPACE do Group-Item
           MOVE SPACE TO PSSDPO-KONTROLOR-INPT.
           MOVE SPACE TO PSSDPO-KONTROLOR-OUTP.
           GOBACK.

1)  After the move in a numerical item e.g.:
MOVE SPACE TO PSSDPO-KONTROLOR.
The SPACE is treated such as the ZERO, i.e. PSSDPO-KONTROLOR has a value 
PSSDPO-KONTROLOR = 0000000000

2) After the move in the group item 
MOVE SPACE TO PSSDPO-KONTROLOR-INPT.
Thu numerical field is filled with blanks i.e. PSSDPO-KONTROLOR =  .

a) Why didn't I get in case of 1) an error (e.g. 'Decimal data error') and 
why is SPACE treated as ZERO?

b) Is the numerical field in case of 2) treated as character field because 
it's part of a group item?

Regards

Roman
Mgr. Ing. Roman MIKLÓŠ 
Prvá stavebná sporiteľňa a.s. 
Bajkalská 30, P. O. Box 48 
829 48  Bratislava 25 
Tel.: +421/ 2 / 582 31 174 
Fax: +421/ 2 / 582 31 109