Does ASA 8.01 or 7.3 support true row locking?

When using ASA 8.01 or 7.3 under isolation level 0, we observed that the
ASA will lock tne next immediate row when updating the columns having
unique constraints in a row. If it supports true row locking, why would it
lock additional row when doing update operation? Is this a known problem or
a misconfiguration? Is there any good workaround for this problem?

Does the ASE 12.5 have the same behavior?

I'm very much appreciated for any help and advice. Thanks in advance.