I read the little paper that comes with the test strips--all folded up with super small print. Looks like BG accuracy is affected mostly by where you draw the sample (finger/palm/other) and if your TRUE BG is <>75. I scanned it to make the section on accuracy more readable.
This is the section I found interesting:
I am only 68% likely to get a reading that is within 5% of true BG.
I am 94% likely to get within 10%, and 99% likely to get within 15%.
It looks like the control solutionrange of 83-125mg/dl is 104mg/dl ±21 which is the broadest range in the expected accuracy table.
The way I interpret this is if the control solution read is 104, then the meter and the strips are spot on. If your meter reads are consistent and near the extremes of this "Normal" range, you may want to consider either getting a new meter or replacement test strips to see if your readings get closer to the 104 target.
I found this via www.fda.gov: http://diabetestechnology.org/FDA/Scott-%20State%20of%20the%20Art%20performance.pdf
It looks like this level of accuracy is pretty standard across all meters.
3546-2011120916.56.09.pdf (1.69 MB)