ap-southeast-1 is Singapore. The better choice for you would be ap-southeast-2 which is Sydney.
But this won’t solve the timezone issue since both regions are using UTC time. I’m working on some changes which will make recurring transactions rely on local time from web-browser rather than using server time. This is because customers within region can be still from multiple timezones.
You should still run speed test and change your region from Singapore to Sydney as this would give you faster speed.