No need to use the Asus Recovery tool when moving between TomatoUSB versions, you can just use the upgrade function in the router's web GUI (there is nothing wrong with using the Asus tool to move between TomatoUSB versions, its just overkill). Be sure to select the "After flashing, erase all data in NVRAM memory". This will make for a cleaner install and eliminate the possibility of any settings from your old firmware messing things up. Also do not use configuration backups from an old version of the firmware on a new version. If you want to transfer settings check out the tutorial Toastman posted on how to do this.