H1B amendment RFE

Hi,

This is regarding my H1B amendment case . I got RFE for my amendment on 11th Oct and submitted requested documents on 18th Oct. Its been more than 20 days, still there is no progress on my case. In USCIS Site, it is still showing status ‘Request for additional evidences was mailed’. This case is premium processing. Could anybody help with timelines for RFE response review?