I have of course tried to fix this, trying all manner of button click variations on the 'Select Increment Length' buttons. The net result of that is that I have gone from two-hour increments to 20-minute increments per button click. This is 'regardless' of what button I actually click! If I click advance 30 days, I advance twenty minutes. I've tried shutting the game down and reloading. Nothing I do seems to fix this.
Have I "done something" to cause this situation? I am not aware of having done anything out of the ordinary. That said, in my newbieness, I do tend to do a whole heck of a lot of stumbling about in the menus and buttons, so I suppose I 'could' have inadvertently done something to cause this.