Why doesn't asus M3A78 mb support Phenom II x4 965?

I don't pretend to know much about CPUs or motherboards so thought I'd ask you guys.

I currently have a Asus M3A78 Motherboard and didn't want to have to upgrade it for a new processor.

So i found out that the Phenom II X4's are AM2+ backwards compatible and began my search for the processor I wanted.

After reading about the AMD Phenom II X4 965 Black Edition I decided it was the processor I wanted with the right price tag for me, but to my dismay despite the M3A78 page saying it Supports 45nm Phenom II X4 Processors, the 965 does not appear on the cpu supported list on the asus webpage.

I called but wasn't given any real reason, i think the guy just read what I had and saw it missing from the support list.

TL;DR:

So I was wondering just why the Phenom II x4 965 BE isn't supported by the Asus M3A78 motherboard?

Thanks in Advance!