Yep. Don't know if the chuff input (purple) is active in any other than the G modules.
Even in the modules with the active input, the timing is far from perfect. Start up is pretty good, but deceleration and stop can be very off, similar to the voltage based chuff.
For voltage chuff there are a few tweaks. In the loco setup screens there is a Chuff Rate setting, but it isn't always very effective either. In an attempt to improve the sync, Doug (MtRR75) wrote a document on setting up the speed table. This is a lot of work, but does help a little. I don't have a link to where that that document was posted on RPUG, so I'll attach a copy here.