I’m a bit shocked by the huge jump in Run time in Full Distance Tri Low Volume week.
The longest run in the plan up to then is 1hr 30min (week 7). Week 11 has you running 2hrs. That’s a BIG increase of 30 minutes.
Is this an error or are we supposed to increase by such a big jump?
I think the increase is 30 minutes because the pace is pretty slow. This workout is more about time running that distance or speed. It’s your longest run on the base plan and the notes say you can lower the intensity as low as required to last the whole two hours.
30 minutes seems to be a big increase in duration on your feet irrespective of the intensity. I’ve always followed the 10% increase per week rule and this flies in the face of that. That’s about a 22% weekly increase of the previous biggest week (week 9), and a 33% increase in the previous longest run from week 9.
Yeah I’ve had a quick look at week 7 through to 11 and you’re right. I would do it as a 9/1 run walk.
Week 9 has a 1h20 long run, but week 10 doesn’t build volume and week 11 ups the early week run to 50 mins as well.
That’s how I do my long runs anyway lol 
My rule of thumb is increasing long run distances in 15 minutes increments. It looks like the first long run of the Low Vol Build is 2h 10m - maybe the duration has been worked backwards from that?
Iirc the general approach differs from standard running plans that gradually increase volume weekly. For a start long runs aren’t every weekend, they’re every other weekend. This isn’t the case in every plan, but it was in mid vol build anyway.