A back of the envelope worst case would be assume they are off by 50 MPH and it takes 10 minutes to fall 10,000 feet at 17feet per second. That seems like 5 miles in the worst case. But, the parachutes don't instantly slow the thing to 15-18 MPH and the wind does not instantly get it to match wind speed and normally it's not dropping into a steady 50 MPH wind from 10,000 feet to sea level.