I should add some info to my post #28 as regards reduction of flare:
1) The camera ...
2) The lens ...
3) ... the use of a white mount board as a target...
Your test is a good one. Non-Flare tests are good.
As Stephen pointed out, taping the step wedge in contact with film eliminated flare.
There are some other common tests...
In a flat tone test, flare does not exist when the subject luminance ratio is 1:1, which would be the ratio when you shoot a single tone test target.
In a flat tone test, people reduce the light hitting the film by increasing the shutter speed and/or closing down the lens aperture. What little percent of flare exists will only add a small percentage of light to what is already a greatly reduced amount of light.
There is one other kind of film test which does have flare and where flare adds exposure to the shadows.
The kind of test where you tape a step wedge to a window, and mask off the extraneous edges carefully, and shoot with camera... That kind of test will have flare.
Here you have a clear step that allows nearly 100% of the light through, a few percent of that will hit the entire sheet of film. Under the 2.0 step you would want to have only 1 percent of light strike the film, but a few percent already hits it from the light reflecting off the bright step and bouncing around inside the camera.
silveror0, You did a contact test... light can't sneak around and get under the 2.0 step, so you really do hit that film with 1% of the light that hit the top of the step wedge.