Article 20.3: More than one change of direction to defend a position is not permitted. Any driver moving back towards the racing line, having earlier defended his position off‐line, should leave at least one car width between his own car and the edge of the track on the approach to the corner.

現在定義清楚了 one move...and "one car width"

至於DRS還在持續修訂討論中....
使用方式, 甚至秒數都可能改變..