All paid orders up to 27/05/2013 16:00:00 (UTC) are part of the first batch.
What about orders that were not payed in full but only partly as communicated and agreed over PM? Only the payed part will get send, all or none?
The partial paid orders are part of the first batch.
I assume you will use the timestamp of the 1st payment and not one reported in the sheet now
Yes.