the 20 can be changed to whatever you would like. The lower the setting the slower time passes. At 20, 20 in game seconds pass for every 1 second of real time. Or, rather, 20 minutes pass every 1 minute, or an hour every 3 minutes of real time. If you set it too low, npcs can act buggy. 5 is probably the lowest I would go, and normally use a value of 10 unless I'm building and really want to squeak out some extra sunlight (of course, it always rains then, so bleh) Does it revert back to 0.01 though every time you enter build mode?