I'm not sure this falls under payroll...but there was no employee benefits option:

You are already tracking mileage to charge the customer, the repurposing to provide a mileage reimbursement vs. charge calculations can't be that complex. We reimburse our inspectors for roundtrip mileage over 10 miles. This is refunded via a line item on their weekly paycheck. This is non-taxable as it is not income rather reimbursement so it's an easy equation round trip mileage after X miles x $0.67 (IRS rate) = reimbursement total.

To that end, we would want to also reimburse inspectors for tolls but ISN would have to upgrade your GPS tool to include/calculate tolls as the GPS solution you have now does not seem to have the sophistication.

Anyway, it's another service ISN could provide at little to no re-write cost.