this isn't 3E, that you can have this big of a gap in skill DCs, everywhere you have a jump of 10, you should reduce it to 3 or 4.
skills in 5e, from 1st to 20th level, mostly go from +7 to +17, counting in expertise and ability jump from +3 to +5
in 3E it's +7 to +30 or more, and +10 or +20...