Yes, Sir, i'm sure! However, I see what you're saying too...
Here is a screenshot from the manual, page #4-25:
Attachment 8778
Green arrows (top of the page) shows what I wrote, the red arrows (bottom of the page) point to what HiVizMan said.
Now, which one is correct?! I did setup a RAID 5 on a RIVE board with 4 disks, and I'm sure that's working. Sincerely, never tried a RAID array with more than 4 disks in my life on any mobo... If it works or not with 6 disks on this mobo, I don't know. Hope that someone here can answer that...