= 5792K + (5792K - 5184K) / (15dB - 12dB) * (12dB -6dB) = 7008K
N.B. I'm discounting the 4672K reading taken at Mon 11-Feb-13 17:18:17 cuz it had then been up for 9 days and, therefore, the 16.6 dB NM isn't the Target NM. But even if I didn't it works out more or less the same. I think 4M2 overlooked this NM and for all we know the target for that reading was 18 not 15 dB.
1999: Freeserve 48K Dial-Up => 2005: Wanadoo 1 Meg BB => 2007: Orange 2 Meg BB => 2008: Orange 8 Meg LLU => 2010: Orange 16 Meg LLU => 2011: Orange 19 Meg WBC