It's intreasting in taking on new responsibilities I heard Cal talk about how this system wasn't working for him and he had infact switched to Trello for this.

So while he does still use this system, it shows that the system breaks if your work doesn't fit being scheduled that way.

All in all, the take away really is that a lot of generic productivity advice, is bad if it gets really specific about the tool, because you have to find what works for you personally and for the type of work you have and i think sometimes even that is different tools at different times.