Hello dear @Taliaa ,
Hmmm, That's a pretty strange thing. Usually, it works better, and people try to increase the dosage more and more, despite the regimen and doctor's prescription. However, there is one more fact - psychological.
I am not 100% sure, but if you feel better on the less dosage, see that it works, and successfully lose weight, you may take it for more time.
Did you ask your doctor about this issue?