Some things to check:

1. Some CDPs will give unlimited mileage, while others do not
2. If you're logged into your Hertz account, try logging out, if you're not logged in, try that.
3. Try changing your country of residence. That very often shows different rates.
4. Try checking rates at www.hertz.pf
5. Try requesting a quote using the link below. It might yield different (better?) results