It's 5 years on and it's still works the same way which is a shame as there is so much potential there to get something half decent like Toontracks.
This pic below is Biab as the Rewire master and Reaper as the slave.
Biab is playing at the same set tempo 120bpm but the tracks in Reaper are a varying tempo map but Reaper uses eleastique to sync Reaper playback rate to Biab so Reaper plays back in sync at a steady 120bpm.
The Plugin needs to work the same way and follow any DAW tempo map rather than just playing back the rendered tracks at a set tempo.
If it can't do that and generate up tracks as fast or faster than Biab then there is not really much point in using the Plugin.