It sounds like you're still in the mindset of low carb as a diet (something temporary) instead of a way of life. If you're going to be doing this for the rest of your life, why would you want to quit before you get to your goal weight?
I agree with Angela. If jumping your carbs to 40 or 50 clears up the brain fog and still allows you to lose weight but at a slower pace, go for it. After all, this isn't a race.
Keeping your carbs low and continuing to lose at a fast pace (for those who are lucky enough to be able to do this) isn't the best way to progress towards maintainance. It's better to be slowly increasing your carbs as you go until you stop losing, then back off to continue losing until you get to goal; that way by the time you get to maintainance you'll already have a fairly good idea what your maintainance level of carbs should be.