You may feel free to disagree with some sort of counter-argument....
But I think it's fair to say that anyone who has watched those 3 loose heads play this year will agree that Sio's scrummaging has been the strongest so far, with the other 2 options having being dominated at times.....
Sio was been shown up trying scrummage at test level last season. He is one for the future, but he ain't there yet