Klopstock after rereading the original post by Mirko I believe you might have a point, the specs look a lot like Orwo UN54 ISO100 negative and reversal, Agfa Formula Orwo = Agfa, Modified APX is marketing speak adding more silver or another silver concentration has a huge impact on the emulsion and makes it a different film.
"Silvermax will be available only from ADOX/Fotoimpex" means they are the only one selling it as Silvermax nothing more.

But maybe I am wrong and even if it is UN54 that wouldn't necesseraly be a bad thing.

Dominik