D-Link DIR-655 :: How To Stop From Dropping Back To Using A Single Channel

I live in a Townhome complex so inSSIDer displays a lot of wireless activity.  I have noticed that many of the routers channels are listed as 6 + 2, 4 + 1, etc., while show only a single channel.  I have been able to "temporarily" replicate this by setting the Channel Width on my DIR-655, by setting channel width to auto, and when I am successful it displays a speed of 300, both in my task bar and in inSSIDer.  However, that is usually short lived and the channel for my router reverts back to a single channel and the displayed speed drops to 130 or 144.  My neighbor's Netgear is rock solid at displaying dual channels.  Well, that and besting my signal strength. :-)

I have the router manually to channel 8 because none of the routers, judged by their displayed strength, use it.So, I guess my question is; how do I stop my DIR-655 from dropping back to using a single channel, which I interpret 20MHz, even though it is set on auto?