And first, let me thank you, and congratulate you for this software.
I want to suggest / ask for a feature that allows the user to set a reminder every X (days, weeks, months), to a task. So that the TimeSlotTracker could let the user know that the period established since the last timeslot its due, and if more time goes by (without adding a new timeslot), that it has been Y (days, weeks, months), of delay.
I have worked on my own, on a similar tool, based on MS Access (that's all I know haha), but it has a limited hierarchy. I'm am willing to send it to you if you want to.