I don't know why the "Tax Code", "Tax Rate", "TaX Amt" fields are grayed out in the VB form. and there is no option to enable these. These are disabled ONLY for US subsidiary.

It looks like this is for a PST taxing authority - perhaps Canada? so makes sense these wouldn't be exposed on the US subsidiary since the US subsidiary wouldn't have a nexus. Instead, if there's PST to reclaim through world wide tax return filings, you would want to track these amounts in a separate GL account (would be system generated based on your screenshot most likely - "PST taxes paid" or similar). This way the local authorities will allow the reclaim/not create a hassle if you get audited.