I emailed the NZ Mobil tech guys. This is what he had to say regarding Mobil 1 10w-30 ONLY.
Either the PAC rim is not up to date, or it's true. I'm waiting to here back from Mobil 1 US today.quote:
Thankyou for your enquiry . Mobil 1 10W30 does contain a small amount
of group 3 base stock which is necessary to achieve the viscosity
requirements for this oil . kind regards Ken Brens