Can I use older versions of Simulation on a newer license

My company is currently looking for ways to cut costs, and one item is dropping the Simulation and Flow add-ins.  Currently, we have several seats of SW Professional 2011 with Simulation and Flow on a floating license.  If we upgrade the network license to standard SW 2012, can we still use SW 2011 Pro along with the Simulation and Flow add-ins?  The need for the latest version of SW is due to compatibility issues we have with customer files - need to be able to modify SW 2012 models for CNC programming.

Thanks in advance for your time.

SolidworksAdministration