The parachute affects drift less than you might think.  The chute is small and is there for stabilization mainly (partially for arming), not for a soft landing, so it doesn't do much to slow the decent.  I've seen BLU-97 drops during 15-20 mph winds - right at the limit of test parameters - and you couldn't tell the difference in impact patterns.  Obviously there has to be some effect, but it's not that much.
				
			 
	             
 
		 
 
		 
 
		 
			 
			 
			 
			 
			