Note the message warning you that RAW files are converted to CFA (Color Filter Array) monochrome FITS picture. It is necessary to pre-process DSLR images with this mode. Indeed, due to Bayer matrix consideration, the RGB result of your RAW image is an interpolate picture. In consequence it is useless to pre-process interpolated data because it will give wrong result. Contrary to RGB image, CFA image represent the entire sensor data with the Bayer pattern. The following image shows you a crop of a CFA image. Note that the Bayer pattern (RGGB on this example) is visible.