For new NetSuite account, is it a best practice to always have the ultimate parent subsidiary as a dummy one, so that we can have another company that is not directly linked to the actual ultimate in parent which becomes a child of the dummy one? Ours is not setup like that. That's why we can't add new subs that are not a child of the current ultimate parent.

Not best practice to do that unless you expect to add sister companies

Alright. So it's advisable only if we expect that our ultimate parent sub will have a sister company?

I'd agree with both of those statements

I remember I asked advanced partner support the same question. So they responded that there is no need to create dummy subsid right now and I can change structure in future using that tool. Actually it's not a tool it's just preference which allows subsidiary structure change:

Thanks everyone! I'm a bit hesitant about that preference due to warnings and waivers but I believe that's the only way then. Are you by any chance familiar if I can literally move the existing subsidiaries anywhere in the hierarchy and/or add new subsidiaries somewhere in the middle of the hierarchy?

You can but it's definitely something you do in sandbox first and then test the shit out of

Thank you. We will definitely.