Bushnell rangefinders, if they show elevation, will show two figures. One is straight-line distance. The other is a +/- number using some algorithm. You then add or subtract that number to/from the straight-line distance to give you the 'true' distance.
For example, the rangefinder gives you 300 feet +25. That means it is 300 feet straight to the basket, but it goes uphill (the +) and the elevation change is equal to an additional 25 feet...making the distance equal to 325 feet.
(disclaimer: I have a Bushnell rangefinder for ball golf and that is how it works...I've also talked to people who have the Bushnell rangefinder for disc golf and they confirmed that is how those work).