Another year? In that case I can hardly believe the numbering is sequential, with mixedupfiles' set being in the high 7400s and the total number being 7500.
Hans, since you seem to be in touch with Scott on a regular basis, could you ask him about this? Up until recently, at least, the big boxes were definitely numbered in the sequence in which they were shipped--based on Mosaic's email to Brad, and also based on the numbers people have posted here for soon-to-be OOP sets that they just purchased. Perhaps this has changed? Or perhaps mixedupfiles' Mobley number is, well, mixed up? Given the recent outsourcing of shipping operations, who knows?