The (Body) and (Heading) font options basically means that you are choosing the font that is dependent on the currently selected Theme Fonts. The theme fonts are selectable via Design > Fonts. If the font name is 'Arial (Body)' then the font is going to be Arial but only because the body font in the assigned theme is Arial.

The theme fonts allow you to specify a font via a theme so that the font can be applied to lots of styles and you can change all those styles at once by altering the theme.

If you define the styles by picking the font without that theme setting then you won't have an easy way to roll out a font change to lots of styles at once.

The complication on this is the way that style settings cascade. Let's say that your styles are set up so that many styles are 'based on' a few key styles. For example, you have a style called 'Normal' that has a font assigned to it called 'Arial'. Then you have a series of styles where:
- List is based on Normal
- List 2 is based on List
- List 3 is based on List 2
- List 4 is based on List 3
Lets say that all these styles have the same Arial font assigned to them.
Now, if you modify the font for Normal, the child styles (List, List 2, List 3 and List 4) will ALSO change to the new font because their font attribute was inherited from a style with that same font attribute.

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Andrew Lockton
Chrysalis Design, Melbourne Australia