On the Subject of Cracking Combination Locks

I now have a lock to which I do not know the combination. Though we can easily fix that.

All numbers are mod 20.

IF YOU DO NOT HAVE TWO FACTORS	IF YOU HAVE TWO FACTORS
First number, GO RIGHT: Take last digit of serial number. Add the number of solved modules. Add the number of batteries.	First number, GO RIGHT: Take LEAST significant digit of each Two Factor Code, and add them together. Add the number of batteries.
Second number, GO LEFT: Take the number of modules on the bomb*. Add the number of solved modules.	Second number, GO LEFT: Take MOST significant digit of each Two Factor Code, and add them together. Add the number of solved modules.
JUST KEEP GOING RIGHT UNTIL SOLVED, though if you want the third number: Add the first two numbers together.

*Includes needies, needies are modules too.