Maps.ini file decides the Order of the maps.
If you have 10 maps listed inside the ini file, It will Go with the ORDER written in the maps.ini.
There will be NO random selection made.
If the map that is in the order but not present in your maps folder directory, It will skip that and Go with the actual order that is "WRITTEN" in the maps.ini
So, Make sure you write it in the correct order you want your Maps to be changed in.