Use a column you aren't using, log simulator time separately.
Some course requirements will allow a certain amount of simulator time for that particular qualification, but it doesn't formally comprise part of your total flying hours.
My logbook has three totals: total flying time, total piloting time (I have a non-pilot flying qualification), and simulator time. Then anybody who needs an answer, can work it out easily.
(Nobody makes a logbook like that, just change the column headings).
G