well your details are true.
But i have gone through number of articles in which it was mentioned that given change interval in the menu 'already includes the idling on signals, traffics, etc'.
And secondly it also depends upon the type of oil we are feeding to car. Fully synthetics has very long interval, than semi synthetic oils, and similarly partially synthetic & mineral oils has relevently shorter intervals.
as a supporting example to your post, lets take example of a mineral oil with viscosity 20/50.
To drive within cities, it change interval is only 3k. But on highways, its 5k.
And for fully synthetics, within city 8-10k, but on highways 12-15k.
So, change intervals strongly depends upon the
1. Type of oil (synthetic, semi synthetic, etc).
2. Driving habbit (soft foot or push paddle).
3. Extra ordinary excessive idling on road signals, traffic (usually in summars when a/c is continously on).
4. Quality of the oil (in punjab, i believe more than 50% shops sell fake oils).
5. Quality of the fuel.
6. Improper maintainess of the engine. (specially if radiator is running short water).
So there cannot be only one reason that we should change oil earlier. And also it doesnot happen only in pak, but also in all other countries (where the weather conditions are hot, very hot, cold, moderate or very cold etc.).
Hence, combination of all these factors produce a general sense or a weak rule to change the engine oil 2-3k, or 3-4k or 4-5k, etc.