Siebel parent record update

We have Service Request as parent IC and multiple child ICs (which are based on S_SRV_REQ_XM table) available underneath it.

External system updates Service Request record using Siebel inbound call. We have scenario where we are expecting change in child IC fields only and modification to the parent IC field is not needed. In this particular scenario Siebel system field 'Updated' of Parent BC Service Request is not getting updated with the latest time stamp.

We are expecting latest time stamp value getting populated at parent BC (Service Request) level because notifications and reports uses this field.