it's in a hidden menu known as MAKER RESERVE mode. CAUTION: if you modify these settings without reading the radio, you can screw up alignment of your radio. Use at your own risk.
Load your CS-3160 cloning software, READ THE RADIO FIRST and SAVE THAT FILE before proceeding. Click the "help" then "about" box in the CS. While this is open, type the word "reserve". You will get a warning about being in MAKER RESERVE and a new menu will appear in the menu tree allowing you to access these values.
WARNING: always write down what you change if something goes wrong. Always work off a READ from radio file in MAKER RESERVE.
You assume full responsibility if you hose anything up.
I am quoting MTS because he is dead center spot on. In full, exactly and accurately.
I'm enough of a coward to go so far as opening the cloning software first so it is clean with no 'artifacts', doing whatever with the radio, then shutting the software back down (and restarting again before hooking up any other radio). That is the only way to exit MR mode.
The reason Icom calls it MAKER RESERVE is that you can muck up a radio in a heartbeat. Writing an icf file from another radio (or a blank file) while in MR will do evil things.
Note that all icf reads contain MR data. Alignment and other data in the MR menu is not written unless the CS-f is in MR mode when writing to the radio.
I
THINK CTCSS Decode Attack is normally 140. Try reducing in increments of 10, but keep good notes. Radios are like snowflakes, each one unique.