I understand that you want to change Key = Name Value = LIVE to Key = Name Value = LIVE- ap-southeast-1a for instances created using the auto-scaling group.
When you create an auto-scaling group in step 4. Customize tags, you can specify the Key and Value tag. Make sure the "Tag New Instances" checkbox is selected (default):

If you have already configured an auto-scaling group, you can select a group and edit it:

I tested these steps and confirmed that new instances created by auto-scaling display the correct key and value:

For reference, here is the AWS Auto Scaling Labeling Guide:
http://docs.aws.amazon.com/AutoScaling/latest/DeveloperGuide/ASTagging.html
source share