That's a tricky law to have on the books. In general, I would agree that computer testimony (e.g. log records) is usually trustworthy, but that's with relatively simple processes such as writing information into a log or recording times and events. However, it shouldn't be applied to larger systems with more complicated functioning such as accounting software unless the results can also be backed up with detailed logs that can be verified to produce the stated result.

The fact that the Fujitsu employees had complete and un-audited access to all the remote terminals should have made the computer testimony unreliable, but of course the post office lied about that and denied that anyone had remote access.