tab settings in -ms macros .RS

[Henry Spencer]

In the -ms troff macros, does anybody know why .RS fiddles with the tab
stops?  It sets one tab stop, the location of which seems to be intended
to be constant on the page regardless of the indent.  (I can't sort out
quite exactly where it is intended to *be*, but that's the general idea.)
The .RE macro puts things back using .RT.

We can't see any point to all this, and it's annoying.  Is this "feature"
actually used by something, or is it fair to consider it a bug?
-- 
				Henry Spencer @ U of Toronto Zoology
				{allegra,ihnp4,linus,decvax}!utzoo!henry