Can you give an explanation for the way your software behaves for the following:
jdreddb.zip
candance.zip
calspeda.zip
vaportrp.zip
gauntd24.zip
wotwc.zip
galpanib.zip
natodefa.zip

Most (if not all of the above) contain files that have identical filenames, crc's, and sha1 values to the parent... and these files show the contents as "merge" files. Why do you create archives that contain these un-necessary files?