timeclock-relative

timeclock-relative is a variable defined in `timeclock.el'.
Its value is

t

Documentation:
Whether to make reported time relative to `timeclock-workday'.
For example, if the length of a normal workday is eight hours, and you
work four hours on Monday, then the amount of time "remaining" on
Tuesday is twelve hours -- relative to an averaged work period of
eight hours -- or eight hours, non-relative. So relative time takes
into account any discrepancy of time under-worked or over-worked on
previous days. This only affects the timeclock mode line display.

You can customize this variable.