[originalscottyg]

Are you returning the summed signal to an audio track and recording it? Or are you returning the summed signal to an Aux or Master fader? It might be possible to measure the latency, then enter it manually in the compensation field of the return track using the user offset field "+/- 0"in the delay compensation view in the mix window. If you are returning the signal to an audio track, make sure to force delay compensation by ctrl-cmd clicking (Mac) the cmp field when the track is in input or record (you don't need to do this for Aux tracks). Then record a transient through your summing chain, measure the offset and enter it into the user offset field, experimenting with + vs - until you get it lined up. I'm not totally sure this will work in real-time, but it's worth a shot. OF course the most reliable method would be to record the summed signal, measure the offset, then nudge it back into place and then do your automation and processing on the recorded track.