Java heap space question - R12.1.3

EBS R12.1.3 running on RHEL 5.

A few months ago clients were getting a oc4j_socket_recvfull timed out error and we'd have to bounce the app tier.

After working with support we able to detect 'Java heap space' errors in the oacorestd.err file.

It was suggested I refer to Doc ID 36285.1 and I made some changes including adding another JVM and increasing -Xmx amd -Xms values to double their defaults.

All was good until month end reports ran when one report generated the Java heap space in the Completion Text.

So I have some familiarity with the OACore settings but perhaps not enough to know what my corrective actions should be here.