25mg per week is a gradual reduction, or at least it is compared to dropping from 400mg right down to 300mg in one hop. Your analogy actually backs up my point rather than going against it - dropping from 400mg to 300mg as the OP mentioned is the 12K once a week, which would be much more exerting than doing 3K every day.

I used 25mg per week as an example of how my medication was tapered down from 700mg when I wanted it done fairly quickly but without causing any adverse or undesirable effects from the cessation of Quetiapine treatment. If you take what BlackSheep is going to do (400mg down to 300mg) per month and change that to 25mg per week, medication will be stopped in the same amount of time because when you 4x25mg it adds up to a reduction of 100mg (400mg down to 300mg) BUT it does it at smaller increments. So it's more like going from doing no physical activity to working your way up to running.

There are no strict set guidlines as to how to reduce Quetiapine. As a person that has been on and off Quetiapine numerous times, 25mg per week was the best option for me personally. I didn't notice any difference in my sleeping habits (except for being able to wake up when I wanted to - not something possible when I was on the drug) and I would definitely not have been able to say the same if I'd have gone from 400mg one day to 300mg the next. That is a HUGE jump in my opinion, and 25mg a week rather than 100mg straight away would be a lot less punishing for BlackSheep.