Question about AP hopping

[Aric D. Blumer]

Suppose that I have two APs, fairly close to each other.  They have the
same SSID but are on different channels.  One is set to have low power
transmit.

A network card running the hostap driver is associated with the
low-power AP while the other AP is turned off.  Then the other AP is
turned on, and the card is able to scan both APs.  It remains associated
with the lower-power AP.

As I walk away from them, I lose connection with the low-power AP, but I
would expect a reassociation to occur to the higher-power AP.  This does
not occur.  Isn't that how 802.11 supposed to work?  Does anything need
to be set in the hostap driver on the mobile device in order to
reassociate to the other AP?

Thanks for any insight you might have.
Aric.