Prodicting INS's movement is somewhat risky. They are unpredictable. Regarding 485, historically, until a few years ago (less than 5 years), CSC and TSC are the slowest ones. Then CSC speeded up and became the fastest one. So did TSC. No long before, TSC took over 2 years to process 485, right now about half year. NSC is always kind of in the middle. As for 140, NSC used to take a year and half to process an I-140. Hard to imagine right now?
There is the bright side. CIS has promised to finish, on the average, an immigation case within 6 months by October,2006. I expect all SCs will speed up soon.