L1b extension maximum processing time

Dear Team,

I would like to know what is maximum time for L1b extension processing?

L1B/I94 expiry date: 20 Nov 2013

L1b I94 Extension applied: 16 July 2013

RFE Received: 12 oct 2013

RFE responed: 28 dec 2013

Till today my application status is “Request for evidence response review”. I have 3-4 month more time to wait( 240 days) period so my employer is not processing my application in premium category.