Filtering out documents in the DTR PIP

When initially establishing the integration between Agile 9.3 and Oracle EBS, we only wanted to send parts into EBS.  Our business team has no need for documents to appear in the ERP system.  Documents are only needed in Agile for design purposes.  Therefore, we applied a filter in the DTR PIP so that documents are effectively ignored by the PIP.  This works well most of the time.  We run into problems when ECO's come through with only documents and no parts.  In this case, the PIP sees an order with zero affected items and fails.  Has anyone run into a similar