>In my applications, the only table that is ever opened exclusive, is the table that keeps track of the last used invoice number and other numbers that has to be sequential. This table only has one record, and is never open more than a few milliseconds, before it's closed again.

You're third. I knew of total of two other cases where this requirement to have sequential numbers existed - one was some guy from India here, perhaps 20 years ago, and the other was Voja Cvejić, more or less my padawan, who was fighting that problem in dbfs, sql server and postgres for years, for a total of three customers. The law is the same for everybody, so it depends on the inspector who picks a customer of yours for this particular torture.

Mind you, I've had contact with some 50 accountants, who covered perhaps a hundred customers, and never had this. But you three did.