Add network seat of SolidWorks to off maintenance (expired) network

Hello,

Our company has 2012 network licenses that are all off maintenance.  We wish to purchase one additional seat to add to the network.  At this point, 2013 has been out for a few months.  Is it possible to purchase an additional seat of 2012 and simply add it to our off maintenance network?

I'm not interested in 2013 because I would like to avoid having to bring all our existing 2012 licenses up to maintenance for 2013 too.

Thank you

SolidworksGeneral