Can you see an option somewhere to switch to a different listing tool, or swap from flat to calculated?

I know eBay have been updating the listing form, but I haven't seen it yet so can't navigate it to trouble-shoot, but if you can access an advanced listing tool or something like that, you should get an option to switch from flat postage to calculated for international (at least, this is still an option on the old listing page, which is what I currently have access to).