I think there's a misunderstanding on how bands/frequencies are considered in relation to what's called the "center" and "edge." Nonetheless, from the Wikipedia diagram you presented yourself, channel 42 (or Channel 36+40+44+48) touches 5.250...therefore, it's covered if running in 80 MHz mode (which is the bandwidth of the channel in question).
With that said, you also need to understand that...by selecting 36, you are selecting 42.
Why?? ...because you have channel 36 (which is the 20 MHz reference to 42 - look at the WiFi table in your Wikipedia link).
I think the image under Older Software and SOHO Routers on this page will help provide more clarity: