Auto Compute data from virtual column without updating table


I have created two tables one has an order ID and other order detail ID. The column “Order ID” has a virtual column which references entries from order detail ID.

My problem is that I want to auto-compute sum of amount against all order detail IDs for a particular order ID. The formula Sum(SELECT(Order Detail ID[Amount],[Order ID]=[_THISROW].[Order ID])) does the job but I have to give user the access to "update table "(or edit order ID) for the calculation to take place.

I want user to be able to add Order ID not edit it and auto compute should happen.

Would be grateful if someone could help me with this.

Virtual columns should recalculate automatically when the app syncs. Is that not happening?