Based on my experience, Hertz on-line quotes have always had this problem (at least for the last 5 years or so) and, even if you get a quote by calling Hertz, the same issue/s exists.
You don't pay the taxes so your "proper" estimated total should be $4.32 which is:
$76.82 (the Hertz on-line quote total)
- $72.50 (taxes)
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$4.32 corrected total (estimated)
It's estimated because the fee/s you do have to pay can change slightly.