I agree with you in theory, but the fact of the matter was the grain silo had no machinery in it, just grain. No other possible source of interference for miles (remote area, on a farm). It only happened when the pilot flew between himself and the silo. Perhaps the silo distorted the signal before it bounced it back... perhaps the electical capacitive property of the silo caused an RC (resistor-capacitor) phase shift which would explain the delay. It only takes 2 milliseconds to shift one servo channel's signal to the next servo.