Paul-
Neither the Before nor After space should show if the item they are on does not have content.
In previous versions of FLEx, the default was to have an “After” space on everything (rather than Before), but for FW 8.3.7 I changed it so the default is to have a “Before” space. The rationale is that sometimes we want a mark after a group of items (such as a comma or period or closing parenthesis). If the last item before that closing punctuation has a space, that would look odd.
However, often people want the Headword separated from other material by two spaces. So I kept the After space on Headword. Also, there are a number other things that are often displayed with the Headword. So for the items that might be part of a “Headword group”, there is still an After space but no Before. Then for the first item after it, that is where I started the “Before” spacing. Thus, the last item in the "Headword group" contributes an After space, and the next item contributes a Before, so there end up being two spaces between the “Headword group” and whatever comes next.
There are also a few other places where things needed to be spaced out more, so the parent of one of these groups might have an After space, in addition to the Before space of the next group.
Anyway, as you note, there are plenty of ways to adjust things. What I describe above is just the default, but users can change it however they want, and we hope it allows people to do what they need to do.
-Beth