The TUNE_CLPBY most-deviant points are clipped before a re-fit is attempted, this process is then repeated until either: all points have deviations of less than TUNE_CLPMXDEV from the polynomial; or, so many points have been clipped that a meaningful fit can no longer be attempted. In the latter case the order will be automatically disabled. You may manually re-fit the trace if the order is still to be processed.
The default value is 1.