Should I send my mediocre test scores if it's not compulsory to do so?
In general, test scores are only used as the minimum requirement for the scholarship. High scores don't help but a score much below median would likely hurt you. If your application statement was well-written and your other materials (letters, grades) were good, I wouldn't worry. If the accompanying materials were weak, then you have much bigger things to worry about than your TOEFL.