When you record a sequence with your keyboard using internal built-in rhythms, that sequence does not always use the correct rhythm in later model keyboards. You can make your sequences upward compatible (for example KN3000 to KN6000) if you first copy the built-in rhythm you intend to use into the composer. Then use the composer for your rhythm rather than the built in rhythms. When you do this, later model keyboards will have the correct rhythm because they are using whatever you placed into the composer. It is true, that with the KN5000 for example, you canít place all of the eight fill-ins into a single composer memory but you can usually work around that by using all of the composer memories or just selecting two of the available fill-ins to use. If you make your sequences this way, you will know that your friend that has a later model keyboard can play your songs almost exactly the way you recorded them, with the only difference being differences in sound samples.