There are two methods the reservation manager uses for calculating bookings that span rate bands:
1. The cost is calculated using the rate band that the booking starts in. This is the original calculation method.
2. The cost is calculated using percentages - whereby it works out the cost for a single night in each rate band and multiplies that by the number of nights in each band.
If you joined PMP after 01/03/2020, you'll automatically be using the new (percentage-method) calculation.
However, if you joined PMP before 01/03/2020, you will be using the original calculation (based on the rate band of the start date), unless it has been switched already.
If you would like us to switch your calculation over so it works out the cost based on percentages of the rate bands, please do let us know.