Alright, maybe someone here can help me...

I'm trying to rent a car with Hertz.
When I log in with my Hertz Gold Plus Rewards account and try to book the car, it will cost me ~660CHF (its a prepaid rate, and it tells me I have to pay ~438CHF now and ~222CHF at the station). When I log out and do the exact same booking, it tells me the price is ~438CHF. Now, in my Hertz Gold Plus Rewards Account I obviously entered my date of birth, so I'm assuming, the difference here is coming from the underage fee, which I have to pay at the station. But when I have a look at whats included in the rate, it tells me, the AGE DIFFERENTIAL is included and under "Not included in the rates" it tells me "Young Driver Surcharge" (This happens when I'm logged in. When I'm logged out, it just tells me, that the "Young Driver Surcharge" is not included). So my question is, can I rely on the fact that the system is showing me that I will have to pay 222CHF because I'm not 25 yet, or is it possible that those 222CHF are something else and they will charge me 222CHF at the station plus the underage fee?

If it is important, I'm going to rent from Hertz @ YVR, in September. And I use the Aegean Gold CDP (since you apparently get an upgrade, if available). I'm renting from the Swiss Hertz Website.

The other question is, is it possible to add a booking with Hertz to your Hertz Gold Plus Rewards Account after I finished the booking process?

Thanks for any help in advance!