Luigi,

...

The problematic part is that section title. The chapter title formatting is Ok (but thanks for showing the way how to deal with these cases for future uses). Applying deepnumbercommand to section didn't help to me...

I've used align=middle instead of alternative=middle in \setuphead[section] (in the first example I've used it for chapter)

sorry for that, I overlooked this change completely. Your solution works as well and it is even much simpler. Thanks, Jan