Revert back?
That would be a bit boring, no? 
Down at 850 it's doing minerside as before the mod, and poolside slightly worse.The output leads to the same direction: Apr 12 17:41:13 bfgminer[23935]: 20s:373.7 avg:360.5 u:309.2 kh/s
I checked with the multimeter, it's certainly a 47k resistor. That's all really strange...
I get the same but if you leave it mining for a while, the pool side will stabilize. Keep in mind that pool side values are way off and it doesn't really matter. All you should care is "accepted" shares and you get paid per accepted share and not Kh/s value.
What pool you use?
Specifically, the pool-side accepted shares are what our pay is calculated from, which may or may not match the miner accepted shares.