Examining Table 10-2 and reviewing Tables 10-3 through 10-6, and character advancement, I would suggest that Table 10-2 be smoother and include meaningful differences between difficulty levels (e.g., include the definition of Trivial). Here is an example.
Lvl Trivial Modrate High Severe Extreme
0 5 8 11 14 17
1 6 9 12 15 18
2 7 10 13 16 19
3 8 11 15 18 21
4 9 12 16 19 22
5 10 14 18 21 24
6 11 15 19 23 26
7 12 16 20 24 27
8 13 17 21 25 29
9 14 18 22 26 30
10 16 20 24 28 32
11 17 21 25 29 33
12 18 22 26 30 34
13 19 23 28 32 36
14 20 24 29 33 37
15 21 26 31 35 39
16 22 27 32 37 41
17 23 28 33 38 42
18 24 29 34 39 44
19 25 30 35 40 45
20 27 32 37 42 47
21 29 34 39 44 49
22 31 36 41 46 51
23 33 38 43 48 53
In addition to the /lvl +1, this table adds a extra +1 (that carries to higher difficulties) at points where characters are expected to have increased stats, acquired items, leveled skills, and have access to magic. In addition, I bumped Trivial for every 20+ level because it seemed in the spirit of the playtest table. Starting the difficulties at +3 per difficulty, up to +5 per difficulty (at 20th), puts some expected difference in the DCs.
