The kit comment was more about where the 'computers' are. For example an old handset will be harder to read than a wrist-mounted OLED display, or an eye-mounted Nerd. One thing I've found is even though there's a Nerd display in my eyeline, I have to constantly remember to look at it, particularly when a lot's going on, e.g. bag-up ascents. Would imagine that a set of HUD flashing lights would be the same where your brain filters it out (like adverts on a website).
The not knowing your PPO2 really does seem to be a recurrent theme.