Agreed with Youssef. Be careful using BCMD. Use XCMD whenever possible. It's called eXternal for a reason. BCOMMAND is a parameter customized to be used by the batch system, XCMD on steroids.
I did a quick test running a phase with manual phase control and aborting by writiing 10 to BCMD and it does work fine. Batch server didn't mind the remote command and keeps track of the phase state.