Fran, smart media is a very poor format, they snap in half very easily, you can only protect them with a sticky label which leads to physical trouble when loading, they have a slow writing speed, and you cannot buy 256 MB cards.
Bill, a sequencer song format is a multitrack sequence without other files, the same as a midi file. Otherwise it would be an easy recording which depended on composers or presets etc
In fact technics songs have the advantage of a compression factor when saved as nx, whereas midis saved as midis on the SD card do not. Therefore if I saved all the midis as nx I could expect to fit a further substantial quantity of songs on the card to those numbers I already quoted.