Yeah, I tried the same channel thing, but I can't change the power, really - the flat is wrapped around two elevator shafts :)
It's an interesting setup, looking forward to an update.
So it's fine if the user doesn't have a shaft between them and the AP. When they move so a straight line from the device to the AP crosses through a lift shaft, they enter the wireless "shadow" cast by that shaft, preventing them from contacting the AP. When they take another step forward the device might "come out of the shadow".
This is a difficult situation to deal with in roaming, where the visible AP set changes rapidly as the user moves a small amount.
TL;DR: I'm pretty sure the parent you're replying to "got it" and you didn't understand what they were trying to say.