Not that it mattered to me other than I just like to see how things go with passport control when keeping packed up the trump documents in case of a fuss as a third country national at Schengen passport control, but I used to keep a table to show that I was keeping track of 90 out of rolling 180 day limits. Showing the tables and even suggesting showing the table tracker sometimes attracted more scrutiny than just verbally telling them where the latest Schengen passport control stamp was for me and that I am leaving so as to not exceed 90 days in any 180 day period if they happened to be digging through each of the pages looking at stamps/dates.