dicountable: in general only the standard tariffs published in written at the local office... these are like the rack rates in hotel.

the difference between holiday, early booking etc. rates and flexible is that only the later can be cancelled, rebooked without any fee.

to book your plat card rates, they need to be stored in your online profile by sixt. after login you see your company/status card rates. ask cs if you have still problems with that