Yes, you can book these with no cash component; when the fare buckets mentioned are available the points cost is generally somewhat higher than that for a classic award.

However, later in the booking process there is a 'slider' where you can reduce the points cost (to a figure no less than that for a class award) - in doing so a cash component is generated which increases as the points decrease.

In general, with these circumstances it often is more beneficial to have minimal points.

e.g. The 96K + $405 award was initially offered as an ~138,000 point award with no cash component.

There's a very good "Sticky" thread related to this on Australian Frequent Flyer regarding this:

Thanks. That makes sense. Will check out the AFF thread.