You are correct about ex SIN fares.
Last April before May the changes, I booked an Award 50,000 QFF point return trip to SIN (MEL-PER-SIN-MEL) for mid January. (BTW, that's a hard time of year for Awards and cheap fares).
Last Month
mrs serfty decided she wished to come along too. Well, the best fare I could find in OZ for the same flights as I was already booked on was ~AUD1800. Six months out, awards seemed an impossibility; I could get to PER ok, just not to SIN or back to MEL

. I could not seriously consider reticketing my own travel as it would cost 5000 + 10000 for new flights + extra Fuel levey costs (If any were indeed available).
Last week, I found a T1 (PS/SG/WP award class) on the PER-SIN flight and while doing some checking entered the QF Singapore site and checked for
one way fare costs SIN-MEL on the flight I am booked on (QF10). Lo & Behold there was one for SGD583 (inc. Taxes etc.).
This is ~AUD468, so with that plus 30,000 points & $142 later,
mrs serfty is booked MEL-PER-SIN and SIN-MEL.
The charge come thru on my Amex yesterday so all is sweet. 8)