I just used boxhelper and found that when you select a number, it does not remove the numbers that are incorrect.
Example:
"You have a hunch the 2nd digit is a 5, 6, or 7.
Possible Choices: 15, 16, 17, 25, 26, 27, . . . , 95, 96, 97
Best Guess: 56"
I input 56
Then select to enter a combination.
"Possible Choices: 15, 16, 17, 25, 26, 27, . . . , 95, 96, 97
Best Guess: 56"
Cheers~