My experience is a little different than yours (though expected) but generally agrees with the use of the processor cores you mention.

My first two cores seem to handle BB/RB requests, the third core seems to remain pretty steady .. but I think that is by design for this processor (fourth core is disabled).
From observation most applications work this way on this system.
I think the zero either got bad info or didn't comprehend the info he got, or maybe misspoke about the core use.

I do not work here, but the benefits are still awesome
Make your sound your own!