We just do the same as for the main oven if we have differing times, open the door, put the second item in, and close the door again
Its quite noticeable, more than with a normal oven how the temperature is hotter at the top. I did a pack of 12 chipolatas at the weekend, put half on top shelf and half on middle and the top were cooked a good 3-4 minutes faster, so probably 20% faster.
I would imagine the very top vs the very bottom would be even more marked.
Like I said, there wont be one fits all, buy what suits your style best.
Like I said ours has a rotissery funtion as well which was the differentiator, having had one years ago and actually having a BBQ version as well, we love the way rotissery cooks chicken.
We do have a halogen oven as well as thats the closest we had previously found to the effect. Just need to get round to trying the airfryer.
Although to be honest compared to the first airfryers these newer generation are far more, mini oven than fryers