Taken from the Star, dateline 2009-03:
PETALING JAYA: RON95 was the buzz at neighbourhood petrol stations as consumers had to quickly grasp the differences between the RON92 (which is discontinued) and RON97 (which has been upgraded) and the new, more environment friendly oil.
The first thing they want to know is how they will benefit from this change to RON95 which retails at RM1.80 per litre.
“About 90% of motorists using RON97 (which has been upgraded to a premium product and sold at a higher price of RM2.05 per lire) can now switch to RON95,” said Domestic Trade, Cooperative and Consumer Affairs Ministry secretary-general Datuk Zain Mohd Dom.
“The price of RM1.80 for RON95 will be capped at this level for the rest of the year,’’ Zain told StarBiz, referring to a statement earlier by Minister Datuk Seri Ismail Sabri Yaakob. “It moves within an active price range, depending on the price trend of oil gauged over a one-month period.”
Malaysia - Petrol Price
Wata - Malaysian Oil and Gas Engineer 
What are the differences between RONs? Also, is this a scheme where they just change the name but keep the content the same just to charge more?
Soha: I can only quote what’s on Wikipedia: the RON is related to the fuel’s anti-knocking properties. Apparently it separate from the energy content of the fuel.
Apparently higher RON takes up more fuel as well…see this: http://politickler.com/?p=3179
soha: do you mean that a higher RON requires more fuel to provide the same amount of energy? I don’t get that impression when I read the article.
I misinterpreted it!!! Read too fast, the two last sentences…hehe. But, is it a good move to take out RON92 altogether? Some old cars might be better suited for that – but then again, you don’t want to provide the infrastructure to serve different needs as it is more costly.
Just to add one important thing – It actually has something to do with anti-knocking for higher compression engines. (higher compression induces more detonation and knocking). generally, higher performance cars would require higher RON.