The frequency settings list is in /usr/lib/lua/luci/model/cbi/cgminer/cgminer.lua

The frequency settings I put in there came from their firmware - I didn't actually delete any of their settings that were in my file.

You can just edit that file if you want or:
If you want me to add more in that's easy enough to do for a next release.
To see what is in your AntS3 before the changes, look in /rom/usr/lib/lua/luci/model/cbi/cgminer/cgminer.lua
If you paste a link to a pastebin copy of that I can add the extras that are in yours (but not in mine) into the next update I do.

The files that I change and are in the archive, you can see the original file just by adding /rom/ on the front of it