Tvheadend

I live in the US (northern California) and one of my channels (58) has changed it's frequency. I successfully did a re-scan on my TV but I'm having problems with Tvheadend.
I use Kodi for my Tvheadend frontend.
I'm on Tvheadend 4.3.
I use a HDHomerun Quatro for my tuner and have done a detect channels.

I think I'm doing it right. I go to Configuration>DVB Inputs>Networks, highlight the network, and Force Scan. Is this correct?

Tvheadend Network discovery defaults to "New muxes only" but I've tried "New muxes only" and "New muxes + changed muxes" with the same results. Which is the correct setting?

I can't get the "Pre-defined muxes" option to stick. I select "United States: us-ATSC-center-frequencies-8VSB", Apply, and then Save but when I Edit it again it is back to a greyed out "Select Pre-defined muxes ...". Is this normal is there a problem. If so, how do I fix it?

I noticed some of the scanned results on the Muxes tab show as failed.

I use a XMLTV file for my EPG, is there something I need to do there?

Thanks

Edit:
I can watch channel 58.1 on my computer using the HDHomeRun Windows app so I know my HDHomeRun quatro tuner is working properly.
Channel 58.1 is in one of the muxes (665.028MHz) that failed the scan. I'm assuming this is because it is the old frequency, correct? How would I get Tvheadend to find the correct mux?