Until now, the exit numbering rules in California meant that an exit
number without a letter suffix meant that there was only one exit in
that same mile, and exits with a letter suffix (A, B, C) were multiple
exit in the same mile.

That is, until Caltrans District 1 (North Coast) decided that they
wanted to have both Exit 667 and Exit 667 A instead of Exit 667 A and
Exit 667 B on southbound US-101.  Why did they request that Exit 667 B
be reassigned Exit 667?  Because there was only one exit in that mile
on the northbound side and it was (of course) Exit 667; they felt that
it was important that the exit for Redcrest have the exact same number
in both directions.

Of course, this is in stark contrast to District 12 (Orange County)
where the exit for SR-133 North is Exit 95 from northbound I-5, but is
Exit 96 B from southbound I-5.

Do other states' exit numbering schemes allow for both unsuffixed (such
as Exit 667) and suffixed exits (such as Exit 667 A) for the same
number?  For those that do allow this nonsense, which comes first?
That is, if you are traveling in an ascending-numbered direction, does
the unsuffixed exit precede or follow the suffixed exit(s)?