SmartList will show you work, open and history. Is this were you got this data from? If you got this data from SmartList then I would verify that the SmartList you are using doesn't have any filters on it. The native Payables Transaction SmartList (Purchasing>Payables Transactions> *) will show you all the vouchers in the system no matter if they are in work, open or history. You will also get Payments in this SmartList which show as a voucher number but it actually uses its own numbering system, you may need to filter these out.
Now that you have done all of this you will probably find that you still have missing voucher numbers. This is because Payables does not try to guarantee that all the voucher numbers will be used. I just tried a simple test, I entered 3 vouchers, 00400, 00401,00402. After entering and saving the third voucher I went back and deleted voucher 00400. My hope was that when I went to enter a new voucher it would start out with 00400 but it didn't, it started with 00403. Your missing vouchers were simply from vouchers being deleted. The large blocks of missing vouchers were from entire batches being deleted.
Terry Blaser
Straight Arrow Consulting
310-272-6240m
tblaser@StraightArrowUSA.com