Billy,
That section is a bit tricky to read because ...
If there is a vertical wall or obstruction *within 8 feet*, the vent must be 2 feet above it, but, because it is within 8 feet of the wall, the vent must also be 2 feet above any part of the structure within 10 feet, thus, the correct thinking is that it must be 2 feet higher than the obstruction within 8 feet and enough higher to also put the top of the vent 2 feet higher than any part of the structure within 10 feet - which may mean the vent needs to be 5 feet high above the higher roof (considering a 6:12 slope, 2 feet horizontally is 1 foot high, 10 feet horizontally is 5 feet high).
In the photo shown, that means that vent would need to be about 10 feet high above the roof - which means guying that sucker off at a couple of heights up the vent, and that it will look U-G-L-Y.
