That New Sub rating as you say is even on our 3 year old Fridge.
IMHO those 1,2,3 stars are LOW ratings and the best you can get is the Number 5 Rating (yellow sticker with Number 5 in Thai written on it)
And please do know the numbers written on it, kWh usage per year and THB per year are just an indication and could fluctuate, for example on our fridge it says 477.06 kWh usage per year, but it's closer to 600. (approx 2 kW per day)
Edit: If you want a Fridge that is efficient with Electricity buy an Inverter