See I thought this was interesting, until I dug into the numbers (
Link). The Reds (10th) are still within 5% of the Waratahs (2nd). To give context are talking about around 10 throws (if my maths is correct, I don't trust it as far as I can throw it but I think it's correct). The Brumbies have the most throws at around 170, the Reds at 150, and then the Rebels on 145, and Waratahs on 140 (numbers aren't exact because I had to work backwards from the percentage and the number of own throws won).
So I think saying 'the Waratahs are most efficient' is kind of a non-starter, perhaps they are more efficient because they throw less, perhaps because they are better, perhaps it's a meaningless number because there are too many factors to say the difference of 5% (again around ten throws) is really significant or indicative of anything more than the line-outs from all the Aussie sides are all working well. (Also for some more context the 'worst' line-out side in Super Rugby is the Highlanders on 82% so were literally splitting 10% into 15 bit. So really it's everyone is winning their own ball.)