You may need to check other flags such as DryBicartFillRequested( Initial Fill), bicarbChamberFillRequested (Filling Chamber F), instead of 'bicarbChamberPregenFillRequested'. Keep Drain and DepressurizeRequest flag as is. This makes sure at any given point, dryBicartExec calls one of the service only.
I think so. the TD needs to know if we are successful in stopping Gen mode for either the DD or the FP. Otherwise, TD is waiting for something else that'll never happen.
whether that should be a separate message response or ACK is up for discussion.