An apple representative has spoken and this is what they said. In a nutshell.
Status at this time is not relevant to when items will ship. Shipping has been pre-determined. Someone who switched to preparing to ship yesterday, may not get theirs til Monday, and those getting prepared to ship today may arrive on Friday. When the processing changes to preparing to ship, it is done in batches and, again, shipping has already been determined. There are many who may not see a status change until Wednesday, but will still receive their watches on Friday.
This is very helpful. Thank you.