Pay it off. A 20 point drop is, what, about a 2% change? And dips from closing a line of credit bounce back.
There are are too many horror stories of student loan servicers acting in bad faith, "accidentally" providing incorrect information or "misplacing" payments. Regardless of interest rates, I would want to kill these debts ASAP especially since they aren't dischargeable in bankruptcy and you never know what kind of financial trouble you'll have in the future.