What if the order numbering system is set up to record individual orders in the tens digit space and generate a random number for the ones place? Sure, it would be somewhat shady, but plausible that 65000 or so orders have been made.
The other possibility is that each order number is sequenced to the total number of stock moved, In which case order 65000 may have been for 100000 units, making the next order 165001 and not 65001.
Just my speculations...thoughts?