If you're paying extra for a nice quality, expensive synthetic, you might as well use it's benefits that make it more expensive.
Part of those benefits is better ability to keep shear stability over a longer interval. So why dump it at 3,000km?
For K20XX owners, changing 2-3times a year is more than enough. If people drive 24,000km a year, then 4month 8,000km intervals are just fine. They got bigger problems to worry about at that point.. like 2nd gear grind
