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.
That's fine if you don't trust it.
I trust the writers guide more than on screen evidence since the evidence is too inconsistant.
We all know that the writers didn't have good technobabble proof readers.
So any number they spout, unless it's backed up by the writers guide source info or actual facts for things like established formula, is to be taken with a grain of salt.