Something fishy about that B6 lag reading. I've just got a B6 (55") to replace my EF950 (of 6 months) because the lag was driving me nuts, and the lag is a night and day difference between the two TVs. The EF950 feels super laggy but the B6 is genuinely spot on.
The EF950 has ~50ms so the B6 is definitely significantly lower than that. And it's definitely not placebo: there is an obvious night and day difference and I had the TVs side by side before deciding to sell my EF950 because I was (and am) over the moon about the low lag on the B6.
I've tested games that were unplayable for me on the EF950 in both game mode and with PC mode enabled: Ratchet, TLOU, Metro. All play like an incredible dream on the B6 with no noticeable lag whatsoever.
Also the B6 SOC is definitely not the same as EF950: this much would be obvious if you ever owned a EF950 and switched to B6.
Baffled by your reading.
Edit: which firmware are you on? And are you in Europe or US?
I'm guessing your lag tester is being temperamental again
http://m.neogaf.com/showthread.php?t=1097292