No, that is by the TNG scale. TNG Warp 9 = 833c.
DATA: I am tracing the transporter beam Bok used to send the probe. The ship is holding position approximately three hundred billion kilometres from here.
PICARD: Plot a course. Maximum warp.
RIKER: Even at warp nine we wouldn't get there for another twenty minutes.
If it was TOS Warp speeds, they'd be home in a few months
TNG Warp 9 = 1,516.38110700484c
Go a page back and look what I posted.
The formula from Memory Alpha is from the official writers guide for TNG.
Whether or not the writers or whoever needs to proof read the treknobabble got it right is a whole different story.
TNG Warp 9 = 833c, as spoken in dialogue in an actual episode,
Since none of these "formulas" were ever mentioned on-screen, they don't count for much IMHO.