BRMS - backup groups not expiring

hey all,  sorry for the length of this post...

My BRMS backup groups have been stable for a couple of months.

I'm working a fairly generic GFS style backup.  full monthly expires
after 1 year, full weekly expires after 1 month and daily incrementals
that expire after 1 week.

One particular tape that was used for dailys - group is set for
"append media *yes" - has filled up even though there are several
expired sets recorded on it.

This tape, has daily backup sets from 6/8, 6/14, 6/21, 6/28 and 7/5
(this morning's incremental backup) which reached the end of tape and
couldn't find another unexpired tape.

What's weird is that there's one item at the bottom of the contents
list that doesn't belong - it's a *LABEL "saved item" with 0 objects
saved, belonging to the Monthly backup group, with a create date of
7/5.  A display of media attributes (option 5 on WRKMEDBRM) shows the
tape belongs to the monthly file group as well.

The latest monthly backup ran without incident sunday morning - 7/3,
on a complely different tape.  the montly backup group is set as
"append media *no".

my questions are:

1.  I think I know why this particular tape didn't expire - the last
backup before this morning was set to expire today - the maintenance
runs after the backup, so it can't expire a tape unless all the
backups on it are expired - is this correct?

2.  If the above is true, why did it only use this tape once a week
for daily incrementals?  why wouldn't it one tape for several days in
a row?  This seems to me to be a poor use of resources.   If it had
used this tape 5 days in a row, it would have expired several weeks
ago and would have long ago been ready for re-use.

3.  why is there a monthly item (with no saved objects) on this daily
tape, saved on a day that no monthly backup occured?

4.  Why is all of this such a pain?

fyi - i'm on V5R3 and reasonably current on BRMS related PTFs (as of
march or april anyway).

Thanks,

Rick