While I agree with you 100% that the 4 day rule ASL adheres to is BS for the type of business they are operating, I will still play devils advocate for a minute...
Since you can alter your bookings using their online system... why wait until the Monday the week of your exam before trying to change the booking when the flooding at Maryborough and Gympie has been known and expected since last week? I now live interstate (still a Queenslander though) and even here in Victoria news about these floods has been pretty widely reported.
If this is your last ATPL exam then you've agreed to their terms and conditions a minimum of 7 times so far, not including any CPL exams, failures and subsequent re-bookings that might have occurred. The 4 day rule is pretty clearly stated in those terms and conditions as well as on the booking confirmation sheet that you are REQUIRED (though not enforced) to print out and take to the exam.
It is pretty piss poor that the level of compassion an employee of ASL can show is rigidly limited by some corporate rule, but hey, this is ASL and CASA we're talking about. It has gotten to the point that I no longer expect any special consideration from such organisations as it seems that employees generally aren't willing to risk an ear bashing from their manager, or do the extra little bit of work that is required to provide what was once called customer service
It's good to hear that someone there used some common sense and that you've been helped out, just make sure you can get it in writing before the fact though otherwise they might get selective memory.
The fee structure that ASL use are pretty insane, although being able to have the exams instantly submitted and marked is a 1 billion % improvement on the CASA supervised exam system that existed before (for ATPL, CPL is a different issue). It's a great thing that the month or two wait before finding out that you've failed and then having to restudy when nothing is fresh anymore before resitting an exam are over. The balance would be somewhere between the two, but anything CASA organises usually turns to sh!t pretty quick