If the Polaris 11 roughly half the size of Polaris 10 is getting that performance it would lend some credibility to the other score, although, maybe it makes the Polaris 10 score look a little low for 1400Mhz, unless the RX 460 was heavily overclocked.
Either way within around 2 weeks of launch is absolutely within the window you start to expect more accurate leaks for sure.
In terms of people asking why AMD aren't talking if they have epic performance compared to Nvidia who already have their cards out, why would they?
Nvidia currently has horrific supply and tiny volume of these cards, AMD are barely losing any sales and if in a month 20-30k Nvidia customers feel exceptionally angry about being badly ripped off by Nvidia, $700 for a performance level maybe 20-30% above what AMD provides for $239 all that is happening is a lot of those guys will be extremely upset with Nvidia and there will be a huge backlash on forums/media in general against their pricing practices and complete willingness to rip off their own customers.
Now if Nvidia was actually shipping in the 10-50k cards a week range, which everything suggests they are no where near, it might make more sense for AMD to be more public about performance and price but ultimately again if they are more open Nvidia will pre-emptively drop prices with some excuse, then AMD will be seen as having to price their cards there to be competitive with AMD. this way, AMD announcing their prices before Nvidia makes any price drops, it's clear AMD want value and Nvidia are ripping people off. If Nvidia are forced to drop 1080 prices to within 40% of a RX480 considering performance difference + some premium, it will look terrible for Nvidia.
Again though, Nvidia is shipping tiny quantities, which still points towards a very low initial quantity and waiting for full production to start bringing weekly shipments, while AMD appear to have been in mass production for several months with a very large supply to launch with wide spread availability in retail stores and with OEMs having 100k's of Polaris 10/11 systems ready to ship.