After recent Eike's changes wrt. handling durations, the last part of the "Calculation Accuracy" page [1] - starting from "An example with dates and times" - is no longer valid. Durations are now handled specially, and the example there will show expected 00:10:00.000000000000000. That part should be removed from the page. [1] https://help.libreoffice.org/master/en-US/text/scalc/01/calculation_accuracy.html?DbPAR=CALC
Pierre F committed a patch related to this issue. It has been pushed to "master": https://git.libreoffice.org/help/commit/9307abb31d6575e714e454861b810bb2122759fe calculation_accuracy, obsolete example with dates and times. tdf#162332