We have Oracle EBS implemented with shared appl_top running on multiple servers (CM server - Concurrent Manager/Admin, APPS server - Web/Apps and DB server - database). While applying the patch via STAT even though we have shared appl_top the same patch is applied twice.
Two stat oracle agents was configured for the oracle ebiz instance
In a shared appl_top environment, you only need to configure one stat oracle agent on the admin server. However you would need to create a script to remotely shut down the services on the other node.