Yes its true bro. Our petrol is not that enriched. But I will say that high octane should be given to the rides who have knocking engines. Without knocking, high octane is just a waste of money.
Explanation:
What are octane ratings?
Octane ratings measure a gasoline's ability to resist engine knock — a rattling or pinging sound that results from premature ignition of the compressed fuel-air mixture in one or more cylinders. Most gas stations offer three octane grades: regular (usually 87 octane), mid-grade (usually 89 octane), and premium (usually 92 or 93).
Source: https://www.consumer.ftc.gov/articles/0210-paying-premium-high-octane-gasoline
In Pakistan the normal grade is 87. I am assuming this because most bids on PSO website give number mogas - RON - 87 to their petrol.
link for PSO: http://www.psopk.com/suppliers/tender_detail.php?tid=1666
link for shell: ITB MOGAS-87 RON MIN (UNLEADAD)
The oil rating for toyota 1kr-fe and other engines are given below:
http://www.omkarmin.com/pdf/toyota-yaris-5-doors-277688.pdf
See?? it is 95! We are using 87! bacharay engine 
More powerful engines tolerate low octane fuels. Less powerful engines really mind with less octane numbers. So 1kr-fe reacts more to low octane fuel than 2SZ-fe and 2NZ-fe engines.
Final note: Hi-octane does not increase mileage. May be a little bit. But it is not made for increasing mileage. It might also not help in a "cleaned" engine i.e. it is not necessasry that you get less carbon deposits with high-octane. It might also not give you more power! I have seen people putting high octane and getting low mileage than normal octane. It just is mixed with anti-knocking compounds. So I recommend that if your engine knocks, go for high octanes. Other wise pasay bachao bhaio!
*1kr-fe to baychara knock kerta hi hay 
Very fragile engine. 87 is too low for it.
What I do: I usually get a 30-70% mix of high octane - normal petrol after two consecutive refills. By the way mine is 2sz-fe i.e. more tolerant to low grade fuel.
Best of luck!
