Aura ONE device-TOC formatting

I use a KA1.

On many kepubs there is a well formatted device-toc (toc.ncx) so that chapters, sub-chapters, sub-sub-chapters and so on are formatted with a different indentation according to their logical position in the structure of the toc. Something like

You can see such a toc structure opening a book into the calibre viewer and pressing Ctrl-T.

But if you examine the structure of the device-toc with the Aura One, the indented structure is lost, and every item is lined to the same level, something like

The question is:
Is there a way to get the KA1 to render the device-toc properly formatted and properly indented according to the structure of the toc.ncx?

ss