Just had another look...
JetStar Asia Airways also fly the route.
I got the following listing from this link on Changi airport's website...
Passenger Flight Planner
JetStar SIN 07:00 > HKT 07:35 (Wed to Sat) from Terminal 1
Tiger SIN 07:10 > HKT 07:55 (daily) from Budget Terminal
Silk Air SIN 08:50 > HKT 09:35 (daily) from Terminal 2
Silk Air SIN 13:20 > HKT 14:05 (daily) from Terminal 2
Silk Air SIN 16:25 > HKT 17:10 (daily except Wed) from Terminal 2
Silk Air SIN 16:50 > HKT 17:35 (Wed only) from Terminal 2
Silk Air SIN 18:35 > HKT 19:20 (Mon to Sat) from Terminal 2
JetStar SIN 19:50 > HKT 20:30 (Tue + Sun) from Terminal 1
Silk Air SIN 19:55 > HKT 20:45 (Sun only) from Terminal 2
Tiger SIN 21:25 > HKT 22:05 (daily) from Budget Terminal
However, Tiger Airways state on their website...
TR152 SIN 0710 HKT 0755
TR156 SIN 1310 HKT 1350 (Fri+Sun only)
TR154 SIN 1600 HKT 1640
TR158 SIN 2125 HKT 2205