Additional Costs to a Capitalized Asset (via CIP Project)

We are testing Capital Projects.

I have created an Asset to a Capital Project with Date Placed in Service 30 Sept 2017

Costs charged to the task and asset lines were generated. Transferred to FA, all working ok.Asset number created and tied back to PA

If I now get additional (late) costs on this Project/Asset, am I able to add these to the existing asset? Or should I create a new (child) asset and add the asset lines to this asset?

Please advise what best practice is in this case.

Thanks

Reina