Back in summer I did the VO2max intervals in a similar manner. They were actually 2min and 4min intervals that I did on a newly resurfaced quiet road close to home. I found I was soon able to pace things really quite accurately - I’d start by a particular telegraph pole and would finish each interval within a bike length or two until maybe the last two or three (out of twelve) when I’d be 30-50 metres short.
I did the threshold intervals in a similar manner on a long hill, again I was generally within a few seconds at my intermediate checkpoints and at the top.
I thought this but @SeanHurley corrected me in that the system does do this - see this thread - https://www.trainerroad.com/forum/t/riding-above-the-planned-power-with-adaptive-training/66984/5 but you won’t get “credits” for power zones that you move into.
@dirt_cruzer The early VO2max workouts in a plan have always been “easy” in terms of actual VO2max intensity (this is assuming that the FTP you are using in TR is reasonably accurate and you don’t have it set at 200W when it should be 250W), the new plans made things easier “to start with”, once AT gets a feel for how you perform you should see the difficulty ramp up. I felt the same with the old static plans, completed them easily. Then about four months in I hit a wall 
the workouts suddenly felt really, really hard and I began failing the occasional workout. That was on the Low Volume plans. AT is conservative and aims to prevent that burnout. Also I suspect that AT takes into account any races/events you’ve added - not much point peaking now for a race in July?