Since two of the denominations were increased in value by engraving a "0" and the oval "1000" is untouched, might suggest that the "1000" remains the highest in the series or set since (maybe) there weren't that many of the original ovals to start with if 1000 of whatefer currency was the highest denomination to begin with prior to the currency being revalued.

Also, note the placement of the additional "0" in keeping the whole, new denomination just as centered in the field as was the previous and unlike the usual French pieces that simply had a "0" added on to the right; unbalanced, for whatever reason..