-must be set up before the deliveries start. When the queue is all in a single
-directory (the default), this happens anyway, but if \split@_spool@_directory\
-is set it does not -- for delivery in random order, the sub-directories are
-processed one at a time (in random order), to avoid setting up one huge list.
-Thus, setting \queue@_run@_in@_order\ with \split@_spool@_directory\ may
-degrade performance when the queue is large. In most situations,
-\queue@_run@_in@_order\ should not be set.
+must be set up before the deliveries start. When the queue is all held in a
+single directory (the default),
+.em
+a single list is created for both the ordered and the non-ordered cases.
+However, if \split@_spool@_directory\ is set, a single list is not created when
+\queue@_run@_in@_order\ is false. In this case, the sub-directories are
+processed one at a time (in a random order), and this avoids setting up one
+huge list for the whole queue. Thus, setting \queue@_run@_in@_order\ with
+\split@_spool@_directory\ may degrade performance when the queue is large,
+because of the extra work in setting up the single, large list. In most
+situations, \queue@_run@_in@_order\ should not be set.
+.nem