Hi Greg, Thank you for your enquiry. In regards to the difference of the oils in the US market and the Australia market, they are actually the same oil in different packing. And actually all Mobil 1 oils are produced in the US, but pack in different locations of the world. I cant remember exactly where the ones in Australia market are packed, maybe New Zealand, im guessing. And I do offer better price on bulk buy. Please check on my company website: www.gllubricants.com Different prices apply to: -1 box -5 to 10 boxes -10 to 20 boxes -20 to 30 boxes Please feel free to contact me for any further enquiry. Kind Regards Nick GL Lubricants Pty Ltd