Anarchy In The UK by Sex Pistols Lesson

Question about reading your tabs for this song. In the video when youre playing the first verse, you show 2 strums with your ring finger and pinky on the 3 & 4th strings and index on the six, and every third strum you lift up only your index. On the tabs for that third strum it only shows you playing the sixth string open, and nothing on the 3 & 4 strings. Is that a mistake or are we just supposed to assume you leave your fingers on those strings like you do in the video? Is that an advanced way of reading tabs or am I missing something?