@katrinakatrinka@uss_oatmeal@actuallyautistic So I heard my mom talking about this system again today, and I think she accidentally said the wrong things yesterday without realizing it. It should be 0.01 for 1/16, 0.02 for 2/16, etc.
She definitely got mixed up yesterday because I 100% heard her tell me that 0.1 was 1/16 in the system. I apologize for the confusion! I think it is actually the decimal inch system after all.