I think a clarification is in order.  The sentence being changed was
perfectly and mathematically correct.  If you laid it out on a
blackboard and parsed it (remember those days?) you could prove that it
said the correct thing.  No one is disputing that I think.  The change
is simply to make it easier on the guy who is reading the manual in a
rush, under a deadline and who might misread it.  His fault but there is
no harm in protecting him a little.