I think the value in tracking lies when health problems arise. Your approach works fine for a variety of healthy babies. If poop suddenly changes color, consistency and frequency, there could be a problem that needs intervention. We tracked all this manually for the first few months, then scaled it down. The most serious "issue" was a week long constipation. If there is a problem for the pediatrician, you can provide a log of all the inputs and outputs without guesswork.