Dear Antonella,
In the predelivered Auditor role ,an auditor could see the Expense reports from users across country versions .If you need to restrict auditor for country version then you have to set up specific roles and then set up access restrictions in such a way that the company is placed in Access context ID.
Please note that Auditors can be restricted by Company Id and this is the only restriction type available.
Thanks & Regards,
Manasa Anantapur