Re: Using Curve Fits and Predictions in place of good old Measurements
Not my primary area of expertise, but I'll take a stab at this. The advantage of using what you describe is that it integrates the errors across all of the readings taken and comes up with an answer. The problem with only looking at individual errors is that a few of the points being read may not be far enough off to fail calibration, but the overall effect is that it should.
If you have the time, I'd sit down with whatever spreadsheet calculates this and put in a few trial "errors" and see what it takes for the routine to flag a failure. Then you can get a feel for how large an individual error is needed, and also the effect of being near the center of the curve versus "out on the edges".
"A Passionate Statistician", ASQ CQE, ASQ Fellow