"all variants at the same time"
I'd like to think so, but I don't. if that were the case we might see some different interior choices on the quads, as it would be no big deal to toss in lusso seats & wood. "watching" peoples order/build dates reinforces this, although I certainly haven't charted or tracked it, just an impression.
and the UK/Aus variants introductions are usually somewhat behind Europe - I can think of no other reason for that occurring.
perhaps for efficiency sake, but it SEEMS that they build in "like" batches.