Let F(G, S) is number of tickets between 1 and G inclusive with sum of digits equal to S. we need to know for each S between 1 and 18 * 9 value F(B, S) — F(A — 1, S). we can compute F(G, S) using DP.
D(pos,b,s) — how many tickets there is with sum of digits equal to s, pos — is position in the string GS representing number G (from left to right), b — currently constructed digits coincide with prefix of GS (with length pos) or not.

i had a similar idea but using DP to count the sums was what i need. thanks

Nice to see the interest in this problem.

I am the Writer, if you need the test cases just give me your e-mail and I can send them :).