Brother,
Plz don't mind, but if Mobil1 dealer has asked you to change after 5K, then I personally cannot believe on that oil.
Just for your reference, in the Slamat-pura area, there is a factory who produces the oil bottles. And would you believe that ZIC, Caltex, PSO, etc. are buying bottles from there. And maker will ask by himself to them that what origin they want to print/embossed on the bottle either its "Made in Korea", "Made in Singapore" or "Made in xyz".
In my previous post, I've mentioned to download the "Bar-code Scanner" in your iphone and scan the code of the bottle when your iphone and it will display the origin of the oil.
Here every oil distributor will say to change even fully synthetic oil after max. 5K because of weather conditions. But I can assure you that if I can buy mobil1 USA made oil, I will drive min. 10 ~ 12K within Pakistan and without any risk.
I am not scare from the stories of the oil shop owners and believe on my own studies, findings & experience.