Brother,
Companies have found the different ways of marketing to sell their products (oils).
Examples
If the oil is 5% Synthetic and 95 regular, the company can advertise or write it as "Synthetic Oil". And people will buy it by considering its Synthetic oil. But infact its only 5% synthetic. But who knows this fact ??
If the oil is 10% Synthetic and 90 regular, the company can advertise or writ it as "Synthetic Oil". And people will buy it by considering its Synthetic oil. But infact its only 10% synthetic. But who knows this fact ??
SIMILARLY, DIFFERENT COMPANIES USING DIFFERENT TERMINOLOGIES TO ATTRACT CUSTOMERS. (Hope you will find it logical).
Now,
If we are living in US/Canad then just use fully synthetic oil of Mobil-1 and run your car upto 20K literally & blindly and without any doubt.
And If we use same oil (mobil-1 of made in USA) in Pak. then we can drive upto 18~20K also. Without having the fear of any internal engine damage. Conditionally oil filter has to be changed after every 5K max.
But whats happening in Pakistan,
Havoline Synthetic oil mileage is 5K (most usual)
Shell's synthetic oil mileage is 6K (most usual)
Caltex's synthetic oil mileage is 4K (most usual)
ZIC's synthetic oil mileage is 8K (most usual)
Performa's synthetic oil mileage is 8K (most usual)
Etc.
Etc.
Etc.
So, we never know that which oil has what percentage of synthetic portion !!!
Reason
Original fully synthetic oil of Mobil-1 (made in USA) is tentatively Rs. 1500~1800/L (If any doubt then check it from Amazon.com)
Whereas the synthetic oils available in Pakistan are Rs. 550~700/L
I believe you can understand it further by yourself.
All the best