Thanks for pointing it out, even i have the same confusion how to put these specs. BTW changed it to the Tested Latency.
One more thing, if core i7 2500k can cross 5GHz+ with H20 cooling, but does it mean Intel should start selling these processor saying they can HIT 5GHz+ out of the box. That's why its called OC with Users Risk & doesn't comes under manufacturing warranties. I know RAM's are of different case, but running beyond the rated Frequency with Voltage Tweak is again a part of RISK !..
Almost all RAM you see is rated at XMP profile. They actually work safely at the XMP spec, but the thing is that JDEC, which is an Intel front, rates RAM at lower to comply with Intel's Uncore spec (1066Mhz for Bloomfield and Gulftown, 1333Mhz for their Extreme counterparts).
You probably wont see RAM marketed for AMD systems containing an XMP profile.
The JDEC spec is marked during chip manufacture, so vendors like Corsair, formerly OCZ(they dropped out of RAM market in case u didnt know),G Skill etc cannot do anything about it. It's just the way the RAM reaches them from Samsung, Hyndai, Epilda, Hynix etc.