Hierarchical builds not possible (TAR/RPM packaging)

The RPM packaging fails when I call it in a lower directory with 
Sconscript(...). The reason is, that the intermediate TAR file contains 
the directory where the SConstruct file is.

I tried to make a tar file in a sub directory without the upper path but 
wasn't successful. The call

       SConscriptChdir(1)
       SConscript('build/SConscript')

does not have any effect although the SCons man page says:

       By default, scons changes its working directory to the directory 
in which each subsidiary SConscript file lives.

My setup:

             -   => SConstruct file
             build/SConscript
             build/bin/a.sh

Whatever I try the builded base.tar.gz contains

             build/bin/a.sh

instead of

             bin/a.sh

This behaviour breaks completly the building of RPM's in subdirectories


My test can be retrieved here:

       https://github.com/wrbr/sconstest/tree/main/build

I also see contradictory statements on the user page and on the man 
page. The user page says:

>> ... unlike standard recursive use of Make, SCons stays in the 
>> top-level directory (where the SConstruct file lives)

    https://scons.org/doc/production/HTML/scons-user/ch14s02.html

That's also what my tests are showing. However, according to the man 
page there should be a way to mimic the make behaviour with 
SConscriptChdir(1).

Please explain.

Thanks, Werner