You would expect the TV to draw more amps while in standby and running a Pixel Refresher than it does while in standby when not running a Pixel Refresher. So I plugged the TV into a power meter and did some testing. Got some interesting results.
1. If I turn the TV off after less than 4 hours cumulative viewing, the draw drops to 0.13 after about 4 seconds of turning the TV off, so I used this as my baseline.
2. If I turn the TV off after greater than 4 hours cumulative viewing, the draw drops to around 0.31 for about 6 min 20 sec, it then drops to 0.13 (baseline). I'd read that the automatic Pixel Refresher takes approx 7-10 minutes, so I think this is close enough to assume that it is working.
3. Here's where it gets interesting. The manual Pixel Refresher is meant to take approx 1 hour. When I trigger one of these, the draw drops to 0.31 for a bit over 5 minutes it then drops to 0.13 (baseline). This is not what I would expect. But here is the kicker. This time the bloody TV did turn on again automatically! Unfortunately I didn't time this as I wasn't expecting it to happen, but I would guess maybe 45 minutes. It did still have a message saying the Pixel Refresher had been interrupted on the screen when it came back on.
2 tells me that the automatic Pixel Refresher is most likely running as it should. This is reassuring, as that was my biggest concern.
3 tells me that the manual Pixel Refresher tries to do something, but doesn't complete the full process. But at least I can be somewhat reassured that the few times I have tried to run it and left it for hours that it looks like it hasn't been going crazy trying to refresh the pixels over and over for hours.
I personally see 4 possibilities (and again, complete speculation on my part):
A. The manual Pixel Refresher starts, but for some reason the TV goes into full standby mode and powers down before it finishes.
B. The manual Pixel Refresher starts, but for some reason fails after 5 minutes.
C. It is a two stage process where it runs a mini cycle followed by a full cycle. The mini cycle completes, but the full cycle fails to start.
D. It is a two stage process where it runs a mini cycle, which then determines whether it needs to run the full cycle. If it doesn't need it, then it doesn't run. This is actually pretty close to what LG support initially told me, but contradicts anecdotal reports I have read. If this is the case though, they should fix the software so it doesn't give you the error message when you turn the TV back on (and update the description to say it only runs if required).