The deep sleep or also known as safe sleep mode is not supported with PGP Whole Disk Encryption and is automatically disabled when PGP Desktop is installed. This results in the battery being drained when the Mac system is in sleep mode. See KB article www.symantec.com/docs/TECH149486 

Symantec Corporation is committed to product quality and satisfied customers.  This Feature Request is currently being considered by Symantec Corporation to be addressed in a forthcoming version of the product. Technical Support filed a Feature Request to add this product feature. Note that an feature request is exactly that, a request. There is no committed date for this request from the Endpoint Encryption Product Management team, nor from the Endpoint Encryption Engineering team at this time. Please be sure to refer back to this document periodically as any changes to the status of the request will be reflected here.