Hi Valentin,
The bill invoices are generated from the insurance carriers with two excel reports, Detail and Adjustments. The payroll reports come from ADP (excel files) with employee deduction amounts that our payroll dept uses to verify against the carrier data. We have a third internal report (also excel) that reflects adjustments and changes made throughout the month (new hires, terminations, leave of absences, and qualifying life events). Sample attached.
Our initial internal review determines if all internal changes are reflected on the monthly invoice and then once documented, we submit to payroll for their review against the deduction report.