Official DDR uses a 1-20 foot rating scale (though modern versions go higher). OmniMix often embraces the "ITG" (In The Groove) scale of 1-13 or uses "DDR X scale" but with user-defined ratings. You will find charts labeled "Challenge," "Edit," and "Kaiden" (insanity).
Running an Omnimix build typically requires modifying the game's boot sequence and executable files. Consequently, you cannot connect a machine running Omnimix to the official Konami servers. Doing so will likely result in an immediate ban of the machine's serial ID. Omnimix is exclusively for offline play. ddr omnimix