Have you tried inserting a click track instead of the metronome...? I use ritardandos on many tunes and need to go from various meters, so I insert a click track for the meat of the tune. Then a second one in double time, i.e. 4/4 becomes 8/4, etc. In this way I can decrease the tempo using the timeisg/tempo markers, the drummer gets to hear the extra subdivisions whic make the ritardamdos much easier to follow. Actually we sent the click out into a Monome and view it visually. Still like to see a fix for you though. I haven't begun to use the plug ins since im still in hardware and DSP. Just another possible work around.