As already pointed out, you have to change /etc/fstab.
I don't think that Suse did maintain two home directories at once. It is rather that your own home mounting overlapped the existing home directory on /dev/sd6. If you unmount /dev/sda5 you will see different contents in home.
Using the same mountpoint multiple times is possible, but only the last mount can be accessed at a given time (it follows the push-pop method). Nice way to hide the contents of a directory, though.