When you spend 40 hours mentally preparing yourself to do a task then you are extremely productive when you actually do it. But the overall performance is still horrible.
I honestly can't comprehend what this means or why it's called "10x productivity". You're productive, but overall performance is horrible? So you do lots but do it badly?
If you spend 40 hours mentally preparing yourself to do a 4 hour task. Then during those 4 hours you are way more productive than other people, but since you had to spend all those extra hours to even get started your productivity sucks. It isn't hard to understand.
So then you take medication and now get started on the task immediately, but the task now takes 10 hours to do instead of 4. Your productivity during the task thus got reduced, but your overall productivity greatly increasied.