@Tanya811
Airbnb uses an "average" price over the last 60days to calculate a Custom Promotion. This is why it's not just taking 20% off your $230 nightly rate. This is done by Airbnb to prevent Hosts from artificially inflating a price and then applying a promotion to the inflated price. Additionally, be cautious when using Custom Promotions, as your weekly or monthly discounts will be stacked on top of the promotion discount if they apply to the period of the reservation. For this reason we don't offer a weekly discount on some properties if we are using custom promotions alot.
How Prices Change When You Use a Custom Promotion
https://www.airbnb.com/help/article/2721
Host Discount Policy
https://www.airbnb.com/help/article/2980