Double check if invoices are correct

I am looking for a freelancer to help me double check our sales invoices on an ongoing basis. The ideal candidate should have experience in accounting and attention to detail.

Requirements:
- Experience in double checking sales invoices
- Strong attention to detail

Task details:
- The task will be an ongoing monthly task
- It will take less than 5 hours to complete each month
- The freelancer will need to double check 100-200 sales invoices each month

Deadline:
- There is no specific deadline for this task as it is an ongoing monthly task