I spent an hour on the phone with their guy John over the same thing, basically he told me, aside from scaling up from 1ml to 4ml on the base when the plants are babies, you want to follow the schedule verbatim.
The lack of ppms is because due to the buffers and other stuff added, it reads differently than a standard base nute, so it would just cause confusion.
Basically they want you to just follow the chart, if your rez requires a lot of top ups between their recommended weekly rez change, they recommend going half strength on the base for topping up.
I was concerned about the pH as well, they told me not to touch it, that the chelates and other stuff they add would keep the plants uptaking everything... I just have it running on a small dwc closet right now, but no yellowing or deficiency signs so far, so hopefully its all good.
This has been my experience too. I started out trying to overthink it like I think a lot of experienced growers do. Luckily I didn't screw anything up really before I relaxed and just trusted the nutes to do what they say they will.
I talked to them on the phone for awhile asking a bunch of questions. Then I thought of more questions, called again... you get the idea.
But yeah that's the way it is. Apparently the pH can be crazy high or low and the plants will still drink up nutes like it's right where it's supposed to be but even so I haven't seen any spikes up or down. Whatever they've done to make it auto-set the pH is pretty impressive.
It's funny that this line is actually easier for newbs to use than experienced growers sometimes. A buddy of mine started growing maybe a year ago and he's used nothing but the pH Perfect and never had an instant of trouble. He literally has no idea how to adjust his pH and probably has never checked it since I showed him how to when he was just starting out. Another guy I know hates the pH Perfect because he couldn't stop messing with it and screwing it up. He just rage-quit and went back to GH and I guess he's happy to constantly stressing over his pH and ppm.
He just couldn't relax and let the nutes do the work for him.