Heungva,
If you have S4Studio it's extremely easy. If not, it's impossible.
S4Studio which will allow you to open up the package and make changes to entries in the Warehouse tab. If not, the following will be gibberish.
The code controlling the Jackpot Challenge is at line 252 of Interaction Tuning Instance DBC1CD1F0E78D2F1, where it says "base chance 20"; just change it to, well... less. I have changed all of mine to 10 times less likely.
For the Beginner, it's at line 244 of Interaction Tuning Instance 8E0B92C8A0CAE079 (base chance 60).
For the Intermediate, it's at line 245 of Interaction Tuning Instance CCFB5FF910249D07 (base chance 50).
For the Advanced, it's at line 245 of Interaction Tuning Instance 258435B3C89EA22C (base chance 30).