I'm transcribing a piece for jazz trio, but I have run across a slight problem. The piece is in swing time, with a 67% eighth note ratio. If I add an acciaccatura (or any other grace note that comes before the beat, as far as I can tell) onto an off-beat note, the grace note is played far too early. It's almost as if it's playing a grace note for the straight eighth, rather than the swing eighth. The grace note works fine if it's on the on-beat. Can anyone give me some advice for how to fix this?