Hi Alan
I have been doing some research and found this fact sheet which looks like it may help explain your meter reading. Although the reading references are 3 digits, so the meter software maybe different.
https://www.yurika.com.au/wp-content/uploads/2022/06/YUR-4194-EDMI-Mk7A-Read-sheet_5-MIN.pdf
In Sydney the meters are actually read by Ausgrid and this data is then passed on to the supplier, e.g. AGL. Perhaps they have the answers.
[Update] Found this info on the Ausgrid site. (not very helpful I'm afraid. It points us back to the retailer, AGL, in this case)
Smart meter readings
Your electricity retailer (the company that sends your electricity bill) is responsible for reading your smart meter. Smart meters are generally read remotely via communications systems, so a technician doesn't have to visit your property. The remote readings are 30-minute interval kWh data, which are sent through to our metering and retailer billing systems by your retailers appointed meter data provider. Your electricity retailer calculates your final bill. Information about smart meters can be found at Australian Energy Regulator.
Cheers
Giff
"Like" if this helps.