I see that it is also incorrect for v3.5.9

What is surprising - is that the logic is okay for python-config -> python-config3.X -> python-config-3.Xm

root@x065:[/data/prj/python/python3-3.5.9/X32]ls -l opt/bin
total 8728
lrwxrwxrwx   1 root     system            8 Mar 26 13:14 2to3 -> 2to3-3.5
-rwxr-xr-x   1 bin      bin              95 Mar 26 10:47 2to3-3.5
-rwxr-xr-x   1 bin      bin             236 Mar 26 10:47 easy_install-3.5
lrwxrwxrwx   1 root     system            7 Mar 26 13:14 idle3 -> idle3.5
-rwxr-xr-x   1 bin      bin              93 Mar 26 10:47 idle3.5
-rwxr-xr-x   1 bin      bin             208 Mar 26 10:47 pip3
-rwxr-xr-x   1 bin      bin             208 Mar 26 10:47 pip3.5
lrwxrwxrwx   1 root     system            8 Mar 26 13:14 pydoc3 -> pydoc3.5
-rwxr-xr-x   1 bin      bin              78 Mar 26 10:47 pydoc3.5
lrwxrwxrwx   1 root     system            9 Mar 26 13:14 python3 -> python3.5
lrwxrwxrwx   1 root     system           16 Mar 26 13:14 python3-config -> python3.5-config
lrwxrwxrwx   1 root     system           17 Mar 26 13:14 python3.5-config -> python3.5m-config
-rwxr-xr-x   1 bin      bin         4429283 Mar 26 10:45 python3.5m
-rwxr-xr-x   1 bin      bin            3005 Mar 26 10:47 python3.5m-config
lrwxrwxrwx   1 root     system           10 Mar 26 13:14 pyvenv -> pyvenv-3.5
-rwxr-xr-x   1 bin      bin             230 Mar 26 10:47 pyvenv-3.5