Board Thread:Questions and Answers/@comment-90.219.177.134-20151015200957/@comment-53539-20151016081651

The -3 bit is to sync it up with DAWS and stuff, for those who want to use Vocaloid as a plug-in to other software (though vocaloid really is unstable when imported as a DAW plug-in at times). If you are using it for sample making or not using it within a DAW or something, you don't really need it.