Pjiang: question to your class - confused student

Teacher Pjiang:

Can I ask you a quesition related to your class about the address?

十月底之前寄往 TSC 的申請，會比寄往 NSC 的要遲拿到收據,why?

I have I-140 pending in NSC, but I live in MA, belongs to TSC for 485 purpose. Which center you think is better for me? If 十月底之前寄往 TSC 的申請，會比寄往 NSC 的要遲拿到收據, I should use NSC, right?

Thanks for help a confused student.