See
this Comm Center thread by Rowland Archer and Peter Prendergast. This was discussed by phone with Archer as well. The idea is to cause the scheduler to focus on partially completed projects so they get completed in less time. As it is now, if you overload it, the projects get "chipped at" little by little and you have to wait a long time before you have completed projects... and they all start completing around the same time.
To do this, my idea is to add another Efficiency Function coefficient that increases as the Project's plans complete. As soon as a Project has one completed plan,. it gets some preference. Then as more of its plans complete, it gets even more preference. This should cause the scheduler to prefer work harder on plans as they near completion, resulting in plans completing and others being ignored.
NOTE: The Astro-Imaging plan generator needs to be augmented to generate multiple projects, one for each "job" of 5-20 hours in a given color, etc. This will require additional settings also.