Not very clear at all, I'd say ED took the safe approach here with using the FCR range scale, I don't know why they didn't keep the ability to change the range scale while in EXP/DBS modes since before it worked similarly to the F15E's MAP mode in it's A/G radar, we can obtain similar results by moving the cursor to the area using TMS up to save the area and then changing the RNG scale, and going back into DBS,it works fundamentally the same as in the videos by wags just that you need to re-enter the DBS mode after changing the range scale. Can't really tell if that's intended behavior or not.