Kill FX not tempo based?

[yrn1]

Am I correct in assuming that the time for Kill Note FX is absolute, i.e. not related to the tempo? It seems to behave like this in my experiments and is really annoying for tying MIDI notes: when changing tempo, they sometimes get untied or tied...

Is there a way to use the Kill FX, but relative to tempo? Using explicite note-off steps is not precise enough for my case. Note lengths are kinda important...