I have created a tool that can be used to calculate the RAP expectations for selling an item based on the current RAP and listing price.

This tool works by detecting if the price is greater than the RAP, if it is it will use the ascending formula instead of the descending formula. The ascending formula works by subtracting the RAP from the price and divide by 10 to receive the change in RAP. We then add the initial RAP and the change together to recieve the final RAP. If the current price is less than the RAP it will use the descending formula. This works by subtracting the RAP by the lowest price and dividing it by 10 to recieve the RAP change. We then subtract the inital RAP by the RAP change to recieve the final RAP.

In the example below, I put in the current lowest listing price for Shaggy and its current RAP. If it were to be purchased at the given price its RAP would increase by 2 with a gain of 0.21%.

Feel free to leave any feedback or suggestions below!