HOMER worries about the no-load fuel consumption and O&M cost more than maybe you think it should.  It figures that it's best to serve the deferrable load when the diesel is on anyway than to take a chance on needing to turn on the diesel later just for the deferrable load because the tank went empty.  HOMER has 2 different settings for dispatching the deferrable load.  It will let the tank go completely empty before turning on a diesel, but we would only let it get to a threshold before putting diesel energy into it as long as the diesel was already on.  Now it looks like that threshold is 100%.  I suspect that may have been something that was changed when we went to multiple types of diesel because this stuff gets a lot more complicated when the choice isn’t just whether or not the diesel is on, but which combination of diesel is on.