Chris, this “one meal only” policy has been in vogue with SQ on the Australia flights for some time. It has caused quite a storm of disapproval from J travellers in Australia and is definitely costing SQ business. Some previous SQ loyalists are now flying QF, BA or EK on this route for this very reason.
SQ has come up with some weak justification of saying they are trying to maximise pax sleep time (the flights from SIN to the east coast of Australia are in the 7-8 hour range – similar to UK-US translantic) but it is really just penny-pinching – you can have dinner, or you can have breakfast – but not both! Ridiculous.