You consultant's advice would appear to be referencing this recent small study:
Where you can read the words "all .... svr .... regardless of duration"
However you might also read it more closely and see
ALL = 19
DURATION = 12 or 24
If they randomly divided the 58% F4s into 12 and 24 week groups we would have exactly 5 people in 1 group and 6 in the other.
If 1 F4 person had failed in the 12 week group that would have reduced the success to 80%!
GT2 is probably the easiest to treat given that Sof+Riba will get a 97% SVR rate - much higher than for GT1 or GT3.
That said you are cirrhotic so you really want to get this right the first time.
If at some point in the future a decent sized study comes out showing that F4 GT2 patients get the same results on 12 vs 24 weeks the worst case outcome is that you have taken 12 unnecessary weeks and wasted $1500 AUD.
Psychologically if you are one of the small minority that don't SVR at least you won't be beating yourself up for not taking 24 weeks.
If it was me I would do 24 weeks.