Hello,
Please find some answers below to your questions.
The reward flight calculator will default to flights departing on the day the search is made. Today is an off-peak day so the calculator will show an off-peak rate today. This will be updated in the future to include both peak and off-peak pricing. We are looking to change the wording on the banner to make this clearer.
In answer to your questions around Air Partners, as long as the flight has a BA flight number, you will earn the Avios rate that applied at the time of booking.
Kind Regards
Louise from the proposition team