However, it is now considered that a dose of 15 mg (1/4 gr) of hydrocodone is equivalent to 10 mg (1/6 gr) of morphine. Hydrocodone is considered to be morphine-like in all respects.

My poor math skills tell me that 15 mg is 1/67 gr
and 10 mg is 1/100 gr. Correct me if I'm wrong.