nIcKo,
There is no built-in ways to do this. The COUNTER function will always start at the first number that you specify, and will reach the end value, it will not keep track of the previous job.
Of course, if the users are willing to manually keep track of the job numbering, you can manually enter the start and end numbers to the COUNTER function. (e.g. COUNTER(1000,2000) will create a counter from 1000 to 2000) But that will require manual user input before each prints. If they don't mind, however, that's probably the simplest solution.
Regards,
Raphaël Lalonde Lefebvre