Which seems relatively appropriate. I was getting a ton of gold for 640 LW gear when WoD dropped before.
People with gold to spare will spend whatever it takes to get that extra little push to get them ready to raid ASAP.
And FWIW, ilvl 850 is closer to equivalent to ilvl 655 gear. 850 is going to be the gear level dropped from Normal Emerald Nightmare and normal Highmaul (First WoD raid) dropped 650 gear.