There is nothing about this in the Wiki (http://forum.mikrotik.com/t/mikrotik-wifi-roaming-expirience/143634/1 )
My understanding of the wording “Allow Signal Out of Range -Time” is: this rule will still apply for the specified time even if the signal is out of range for this active rule.
There are access-list rules that allow authorization (so you will not get kicked off if you do not satisfy the signal level but within the specified time ) , and there are rules that do not let you authorize and reject the association. If the signal is out of range for this active reject rule you are still rejected/banned if within the specified time. The banned reason is given in the log (because there are other banned conditions than “not allowed by access-list”)
If you have a few AP’s in range, and walk around with your device, you are easily banned from all those AP’s.if the default 10 seconds are used. (You need special action to see the Allowed Time column in WinBox and the default is not in the config export. So it is easily overlooked). The wiki example is a trap for bad wifi experience with portable devices with AP’s in adjacent rooms or inside&outside.