The A option can be used as an equivalent to the C
option by choosing TOL
in terms of standard deviations instead of probability, and returns z values
in DIFFS for each bin.
The A option is intended for setting by hand absolute minima and maxima.
To restrict an efficiency between 80 and 100%, load the reference histogram
with a mean of 0.9 (via HPAK) and the error bar of 0.1 (via HPAKE),
and use HDIFFB with TOL=1.0 and the A option.
The N option should also be selected for this application.