Sum of parts can be a few minutes short of total

[caktus-philip]

At the end of the month when I tally my hours, timepiece’s GUI reports my time for individual projects in hh:mm. Internally, timepiece also keeps track of seconds.

When I tally my time, my sum is only accurate to the minute, while timepiece’s is accurate to the second. This sometimes results in a different sum.

For example, if my time (hh:mm:ss) is as follows:

Project A - 01:00:30 
Project B - 01:00:30 

Then timepiece's GUI will report this as:

Project A - 01:00
Project B - 01:00
Total     - 02:01

Thanks to @rebecca-caktus for debugging this for me some months ago.