Hi Zac, I’m on the same plan, 4 weeks out from a 15 mile, 5,000ft race. I came into the plan halfway through, although was adhering to the UA principals before committing to the plan.
In the latter stages, you are doing 150-180% of the total, I always go for the top end and round it up a bit too, but when you add in the vert, it is still very taxing.
I have been pretty religious to the plan, and in the last 6 weeks my performance is unrecognisable to previous fitness levels, so I can only suggest you stick with it, as ‘easy’ as it may seem from the outset.
I hope that helps, regards from NZ.