Oh that is useful to know as I was on the Singapore Airlines site and they were selling seats for the Adelaide flight in September but wasn't certain if they were running as they are also selling for Darwin flight and I don't think that is running. There seems to be plenty of points redemption options at this time as well.
They haven’t yet published their schedules for September, but it is probably wise to assume they will extend their August schedule of one daily into ADL on the same day of the week. I’d therefore look at booking specifically on that day of the week rather than any other.
Schedule available here:
Singapore Airlines and SilkAir Flight Schedules - November 2020 to January 2021
www.singaporeair.com