My guess is that when the program reads something from the INI file that doesn' t match the values specified in the XML config files, sets the GUI slider to low. As soon as you adjust it and go back, if the INI file is not read-only it gets rewritten with the with the correspondant XML values.
What bothered me is that i couldn' t change other parameters, such as hud size and volume, so i made a backup of the XML file and edited the values there and left the INI with full access.
Any extra tweak is not going to be touched unless it goes over the hardcoded thresholds.
By the way, i' ve noticed that v1.03 has been set with lower LoD, mesh rendering, grass draw distance and shadow quality "circle". It runs much better but with more pop-ins and fade-ins, no matter how high i set the distance parameters.