Well I guess I'm just lucky on the DX10 ready files because I did just what Rod cautions not to do. My method was some what convoluted but I did mine this way.
1. Download the DX10 Ready zip file.
2. Extract the zip file to a temporary location.
3. Compared the files inside the scenery sub-folder of the unzipped file with the files in my RTMM scenery sub-folder for the same scenery.
4. If the files had the same names then I simply copied and replaced the old .bgls with the new ones.
5. This does require that you inspect both sets of files for identical names or additional files, and also copy those files to the correct place.
6. All the support files, jpg, and txt are the same so those were just omitted.
7. Once the transfer was done I could delete the unzipped files and copy replace the zip file to my archive location to have on hand.
8. Rod's cavat about files with season switcher capability is very true and there were two new DX10 ready downloads that needed to be altered which has been done.
9. May warning is before you begin replacing the DX100 ready file is to make sure your seasonal switcher is set to no season so all the files from RTMM will be on the same page so to speak.