I prepared a landslide susceptibility map. Now, I need to reclassify the raster into different susceptible categories and calculate AUC (Area under curve). I have experienced, raster when classified in equal interval, natural breaks or quantile, they all have different results. Natural breaks and quantile are likely to give better results.

I am confused if AUC is prepared being based on equal interval (100 classes) or can be done for any classification (100 classes).