It's bollox at 6C+ and I think/hope is going up in the new NWBible. I think even Doylo agreed it's a sandbag. I tried it when I was doing a lot of 6C-7A stuff in South Snowdonia and couldn't make any progress. HTH.
New NWBG has upped the grade to a F7A, and has mentioned, that starting, matched on the right side is harder than "Kung Fu" start!
I knew it clearly wasn't me just being weaker....