Transition F/I

Can someone clarify what Andre means when he says at the 1:20 mark when he says at WOT we should ensure the AFR is sufficiently rich as low as 85kPa? Why would you be richening the fuel mixture when the air flow is more restricted? Would it be because of the heat generation?

Link to the video: https://www.hpacademy.com/dashboard/courses/understanding-afr/the-afr-target-map-full-load-na-transition-fi

This is because at WOT under ideal conditions the MAP should be 100 kPa (well 101.3 but let's not split hairs). In a real engine however with potential intake restrictions, this may cause the actual MAP at high load to drop a little bit to perhaps 90-95 kPa and we want to make sure that the cells around this sort of MAP value are still sufficiently rich. That's why we follow our WOT targets down to perhaps 85 kPa.