Everyone loses differently. Some do lose better at higher carbs. It's not just about how fast you can lose though.

The question with staying at 20g is are you willing to do that forever? If you do 20g until you reach goal then suddenly try to move to maintanance level carbs, you will retain water weight if nothing else.

Moving up the carb ladder helps your body build a tolerence to carbs again. It also helps itentify any trigger foods or food intolerences. Some people can't handle dairy, while others find fruit sets off sever cravings. It's also important to figure out what level of carbs you can tolerate. It's easier to move up slowly, then hit goal and then try to play guess the amount.