Well that is a "simple" hashing procedure, no current mining software works that way.  Part of the blockheader include the timestamp.  The timestamp doesn't need to be exact so there is no reason to not run the entire nonce range and return any found shares.

With X-Roll-NTime the local miner software can increment the timestamp for a period of time further reducing the number of getworks needed.  In theory if X-Roll-NTime was set to say 300 sec, the local miner could continually update the block header until it gets a longpoll (notification of change in blockheader -usually because new block is found).  IIRC most pools use a more conservative n-time-rolling value of say 10-30 sec.