Jay,
FWIW, I have one of Scott Parker's super-tuned RCBS 10-10 scales, as well as a Redding #2. Years ago, I got a 10-10 when my first Pact dispenser died because everyone told me it was the best available, blah blah blah. Hated it, or more specifically, mine would 'stick' and I didn't like the way the adjustments work (personal preference) - so I sold it and got the #2. 1.5-2yrs ago, when I was in the midst of pulling out what hair I have left due to my Acculab VIC-123 acting up, I talked to Scott and sent him a brandy new RCBS 10-10 (dang things had gone up in price noticeably!). I would have rather sent him a #2, but he said even though he had one himself, he didn't work on them for others as he couldn't guarantee the results like he could the 10-10.
I'd weighed a bunch of charges (50) across the 10-10 before I sent it out, and the #2 as well, and cross checked them on the VIC-123 (non-varying weights it did fine with - but trickling just drove mine batty), and then again when the 10-10 got back. I don't think I have the numbers handy any more... but the interesting bit (to me) was that while the 10-10 was noticeably better after being worked over... the #2 was still at least as good.
German,
This probably makes not a whole lot of sense, but my observation thus far is that the single-kernel weighing hasn't been the secret handshake to consistent single digit ES thus far - or else I'm just doing it wrong

Lower, yes. But single-digit seems to take something else - more of a load tuning thing than just the scale. I've had some loads shoot nearly single digit with thrown charges, and several that would come close with charges dispensed by the Chargemaster. Now for the weird part - about February last year, I went down to Douglas Ridge outside Portland to do some long-range load testing as FCNC was coming up in March in Sacramento. I took a few loads along to test different things such as the effect of pointing, meplat uniforming, etc. Among the loads were ones that were identical except one batch was straight off the Chargemaster, and one was weighed out on the GD-503. It was raining like crazy, so I stopped plotting after about five shots - nothing short of a china marker/grease pencil on a plastic sheet was going to work in those conditions. Turned out that the guy pulling targets was numbering the pasters as he put them on, so when he came back with the repair centers we were able to back plot the shots. The difference wasn't night and day, but there *was* a noticeable difference in vertical @ 1k between the two - though I never could see much appreciable difference over the chronograph.
YMMV,
Monte