This plugin has a different strategy concerning the background level,
however: It puts the average of the ROI to 128 for 8-bit images and
32768 for 16-bit images, so it may result in overflow for the forground.
If you have 8-bit images, or 16-bit images usuing the full 16 bits, you
will have to convert to 16 or 32 bits, respectively, before applying the
Another way to avoid saturation is setting the B&C as descibed on the
plugin page and checking "Shift Values to Display Range".
For 8-bit and 16-bit images it will also apply a calibration, such that
the background level is zero.
Of course, you can record these steps with the macro recorder and then
create a macro for it.