Australia Post Shipping Module

[hybrid]

I've just noticed this bug and I can't work out why.
After choosing a shipping option, once I go through payment options and get to the summary screen, it's always using the first shipping option in the list, even if that's not what I chose.

If I go back to my cart and go through the process again, it remembers the option I chose.
I've tried debugging this and I just can't see where the issue is.

I've attached a couple of screenshots to show what I mean.
Any ideas?

[hybrid]

Sorted this one. Can't have underscores in the service code, so had to remove them. All working fine now.