PO Change Validation Checks

We are new to SNC. We have created our own settings for POC1 PO_CONFIRMATION_DELETE and POC1 PO_CONF_RELEVANCE_CTRL in SNC. These setting are active. Our concern is that when a PO Change is sent for a PO that a supplier has already confirmed, the entire PO confirmation is deleted even if only one line of a multi-line PO is changed. Have other customers seen this behavior? Since SNC requires all PO lines to be sent with every change, is there a setting that will limit which lines are deleted?

Thanks!