I understand your confusion, but please let me explain:
Correction files in RadiMation are used for several purposes, and depending on the situation where a correction file is used, the contents can be interpreted differently.
In the past, a correction file only had 2 columns: A frequency column and a correction column. Nowadays a correction file can have multiple columns, and the type of the second column can be modified (by pressing on the 'Columns/Units' button on the correction file window). (
http://wiki.dare.nl/wiki/index.php/Chap ... tion_files )
In Chapter 14 it is described which correction files can be used to correct a cable loss (
http://wiki.dare.nl/wiki/index.php/Chap ... Cable_loss )
Because of history, the correction file that can be attached to a cable, can have a frequency and a correction column, where the values in the correction column are interpreted as cable loss. The positive values in the correction column are thus interpreted as dB values as a cable loss, a cable attenuation.
Once we added the possibility to select an 'attenuation' column in a correction file, it became possible to attach a correction file to a cable that contained a frequency and an attenuation column. The positive values in the attenuation column are then interpreted as dB values as a cable loss, a cable attenuation.
Once we added the possibility to select a 'gain' column in a correction file, it became possible to attach a correction file to a cable that contained a frequency and a gain column. Gain is of course the inverse of attenuation, and thus a different interpretation of the values in the gain column is done. The positive values in the gain column are interpreted as dB values as cable gain. These values are inverted to represented a cable attenuation (cable loss), before they are used to correct the cable.
This indeed results in the formula that you specified: Output level displayed = Measured Signal Level + Cable correction Attenuation - Cable correction Gain
I hope that this resolves your confusion.
Otherwise please let us know.