NikT:
Here's how it generally works:

 

•  Vendor (Samsung, HTC, Nokia/Microsoft, et cetera) identifies an issue/is alerted to an issue by network operator partners/is releasing a software version bump with new features
•  Vendor builds market/model-specific software
•  Vendor sends network operators the software build for testing
•  Build is tested, which for us takes a maximum of around one week if no major bugs are found
•  Build is given network certification approval for deployment - Vendor deploys build at their leisure*

*This is the key point. Some vendors do this immediately, some take 5-12 days, others just don't get around to deploying it at all. We do not have control over this and do not receive notification when this occurs. Unless it's an extremely urgent bugfix, it will generally enter a queue for deployment and become available when it reaches the front of that queue.
I can tell you with 100% certainty that NZ market Lollipop software builds have not been given to the operators by Samsung for testing yet. Lollipop OTAs having been pushed out in other markets means nothing when it comes to Samsung NZ, because they have different builds for essentially every market and network operator they sell into, and many different hardware variants to boot.


 - Nik