Thank you for taking a look at this for me.

I went to Reservation, San Diego Airport, April 1, 3 PM to April 6, 11 AM. Clicked Select My car.

Intermediate SUV is $240.30 Pay at Counter, $204.24 to Pay Now.

I click Pay at Counter

Then it says Base Rate $240.30, Fees & Taxes $111.28, for an estimated Total of $351.58.

I check all options are unchecked.

I click Proceed to Checkout.

Same prices.

Agree to Terms and Conditions

I click Reserve

I get Your Car has been Reserved. Except now, Estimated total is $384.48 (not $351.58), and shows a base rate of $267 (not $240.30), with taxes and fees at $117.48.

So the rate went up when I hit Reserve.