The common credit reporting manual used by the big-3 CRAs and Innovis, titled the "Credit Reporting Resource Guide," includes the detailed description of all official account types and reporting codes and formats, and is the bible for credit reporting designations, terms and codes.
That Credit Reporting Resource Guide does not provide any account type, designation, or reporting code with that title, or reasonable variation of either Open Service or Professional type account.
It is likely a term that is used by the credit industry in general, but not an actual account type with respect to credit reporting that is recognized or used by any of the CRAs.
If a given creditor or business is using that term, I would make inquiry directly with them as to its meaning and use.
