What does ADSM consider a changed file in NT?

We have just started to backup NT servers with ADSM.  Our ADSM server is
ADSM 2.5.1.13 on AIX 4.1.4 and the NT servers are 4.0 with ADSM client
2.1.0.6.

We are seeing many instances of files which are backed up even though it
doesn't look like they've changed.  For example, there is a file which
has 4 backups.  When we do a query of the backups from the client, we
see that the size and modification date/time are exactly the same.  We
then restored the 4 backup files so that we could compare the file
'attributes' to see if we could
figure out what was 'different' about these files which would have
caused ADSM to back them up.  1 of the files we restored had different
permissions, so I can understand why ADSM would have backed up this
file.  However, for the other 3, all the attributes looked the SAME
which makes me wonder if perhaps ADSM looks at the LAST ACCESS DATE (one
of the NT attributes) to determine whether or not to backup a file. I
hope this isn't the case,  since you can have the LAST ACCESS DATE
change because you access a file (i.e. bring up a spreadsheet in Excel),
however  if you may not change the contents, (i.e. the MOD DATE/TIME,
SIZE) don't change.

 Questions:

 1. Does anyone know EXACTLY what attributes on NT ADSM looks at
     to determine if a file is eligible to be backed up.

 2. Does ADSM consider a file eligible for backup if the LAST ACCESS
     DATE has changed, but the modified date/time or size have
     have not changed?  If so, any ideas why?

 3.  Is there any way to control WHAT ADSM looks at to determine if a
file
     should be backed up? (i.e. any parms on the server or in the client
     DSM.OPT file).


Thanks.