When you order a document, you can add 2 statistic fields. We want to store also these information in MARC subfields, either at item level or at biblio level. I think it is not possible at present... So it would be an appreciated enhancement. M. Saby Rennes 2 university
Maybe Bug 11844 is interesting for you, it is nor for the statistic fields, but since 23.05 you can add additional user defined fields to the order lines. They allow you to create a field in the MARC record.