Compile in IDE vs Editor regarding hot reload and Editor restarts

When compiling in the UE4Editor it generates a module with a numerical suffix for hot reloading, when building in the IDE you also need a suffix in the module for hot reloading. But how does the UE4Editor know which module to load if you decide to close down UE4Editor and compile in the IDE for a while then load the UE4Editor and test the module?
Which module is chosen?