Nested grids - help appreciated

[klickreflex]

Hey there,

I'm really starting to like Zengrids but have one issue I can't get solved:
How are nested grids supposed to work?

I have a basic layout with 12 columns: 3 col sidebar, 9 col main.
Now I told the main column to be a nested container using zen-nested-container() after zen-grid-item() of the main column. When I now start creating new grid items inside main they seem to be calculated based on a new 12 column grid, based inside main column, this of course results in having smaller column widths, when I actually want to have the same grids inside my nested grid.

Is this supposed to work like this or am I missing a point here?

Background: I'm creating a zen subtheme for Drupal and want to layout my individual fields inside the main column (using display suite or node templates) to be on the grid. Is there another way to tackle this?

Thanks & regards,
Daniel

Update: It seems to work the way I need it if I set the nested grid to have 9 columns using $zen-column-count: 9;
Is this they way it's supposed to be done?