sleep command doesn't take effect

Hi, we were working with Orch start service automatically script, ..set init.d WLSERVICE file script to start Orch and a few second later) AIS service, but both services start at the same time!... seems the command sleep doesn't apply.

extract script:

    su - oracle -c "cd ${ADMIN_HOME}/bin; ./startManagedWebLogic.sh Orch > /u01/oracle/Middleware/Oracle_Home/user_projects/domains/base_domain/log/Orch.log 2>&1" &

    sleep 30

    su - oracle -c "cd ${ADMIN_HOME}/bin; ./startManagedWebLogic.sh Ais > /u01/oracle/Middleware/Oracle_Home/user_projects/domains/base_domain/log/Ais.log 2>&1" &

what is the root cause, sleep comand doesn't take effect?