Hm, yes, good point. Orbiter does infer the ranges from the [lvl,ilat,ilng] indices of the tile, rather than the values stored in the file. Nonetheless, I should write the correct values to the header files, if only as a sanity check, even if they are redundant.
This current "lack of enforcement" actually helps to move elv file to a different location and rename it. Not sure how practical, but may be helpful when learning tiles or debugging something. If the indices and/or coordinates will be embedded in a tile, they better not be enforced too tight, to allow for some cheating