Difference between lamp brightness and exposure slider

[Jstar]

I am currently trying to scan 35mm slides (Kodachrome, I am using a Kodak Kodachrome Q60 It8 Target.). After doing a prescan the image is too dark. I can adjust the overall brightness of the image by going to the options menu (special) and increasing the lamp brightness or I can increase the exposure slider in the picture settings windows. Are these too adjustments doing the same thing? What is the difference between the two adjustments? Will either adjustment require me to do a new IT8 calibration using same values when creating the .icc profile?

[LSI_Ketelhohn]

Lamp brightness truly adjusts how much light is used to scan the image.
This requires a recalibration at the new setting, because the colors are seen differently by the scanner.

The Exposure setting is a software sided option simulating different exposure values and does not require a recalibration.