I think the person who sent you that was.. wrong :/
I know they don't offer the paste with the Vyper chassis, and PCS have said that this is because the design of the chassis makes repasting trickier, and because the standard paste and standard cooling on the Vyper are so good that there's no need to offer better paste.
But on the Octane, I've not heard that. And they clearly do offer the better paste because I could buy it if I wanted to in the configurator!
.. unless they have started just using Thermal Grizzly on all Octanes as standard or something.. but why sell the CM paste still if so...