We use click and drop (OBA) and they do daily manifest except weekend. Once the label is printed, they will update Amazon that the package has been dispatched.
My view is this, some bigger operations will be packing and stacking them in the corner all day. May be there is 1 collection per day or may be 2. You will not know which one has gone in which collection unless you really looked but as far as you are concern, it is packed and ready to go.
In ERP software, the sales process in simple view is quote -> order -> pick -> create delivery note -> pack then PGI (post goods issue). At PGI point, that transaction will generate an invoice and thus debit customer account and credit company sales + P&L account.
Amazon use the same logic that money is release to us once we confirm dispatch, which can be 9AM or 2 sec before the mailbag is picked up. It depends on your procedure, when you hit that button saying you have ship that order. If you download all orders in morning and then start packing, do you hit each one as you go along or at the end? If you doing weekend packing like a few weeks ago, you have already packed the box and it is amongest the mountain sitting there waiting to be collected.
I once was asked to go retrieve it as the customer want to cancel and I said to him, sorry i wont be able to find it but send it back when it arrives and I will refund.
So my argument is there is nothing wrong, as long as they have been packed and marked as dispatched.
On another note, I had orders from Germany came in late Sunday night and the dispatch date is same date. I have queried this with CS as there is no way I can get them out at 2100 on a sunday night, the quickest will be 0900 Monday morning. I was told it was a clich as they are ahead of us and somehow that confused their dispatch calculation.
As another poster pointed out, I have only just switch EU back on and they have been off in December and only FBA available as there are too many things that can go wrong logistically. I have enough to deal with for UK already.