The pagecounter returns "Custom" as the paper size for any paper sizes it does not recognize.'
If jobs are being reported as “Custom” when they should in fact be one of the standard paper sizes, you may need to create and configure the following registry key on your Print Servers:
HKEY_LOCAL_MACHINE\SOFTWARE\Pharos\Page Counter\Paper List
This string value can be set to a comma-delimited list of media sizes (e.g. “A3,A4,A5”) - only sizes in the list will be recognized. The order of the list is not important.
The reported size will be the smallest size on the list that is at least large enough to hold the page. If no size on the list is large enough, the media size will be reported as “Custom”.