A: Firstly, to see what the various binning entries are take a look in the contour_binning.xml file.  This file resides in the data folder on the ioGAS installation folder (eg. C:\Users\USERNAME\AppData\Roaming\ioGAS\userConfig and contour_binning.xml file to binning.xml).  To add a custom bin entry say for the 50th and 80th percentiles at the bottom, copy and paste an existing bin entry and make the changes as required.  Save the contour_binning.xml file and re-start ioGAS for the changes to become available.  The bin percentiles represent the maximum value of the bin range.