Yes, this works and you now pair e.g. a tiff file as well. Awesome, something I wanted for a very very long time now!
A little confusing, however is that the filename is changed into “xxxx.yyy+jpg" event though the paired file is a tif, not a jpg. Either change this to show the actual paired file extension (which can be multiple), or simply leave it off and include only a marker to indicate file pairing (e.g. just a + sign). Also the menu entry should not read just “Combined RAW+JPG”, but something that illustrates better that it is combining all matching files. But, the feature is really much appreciated!