Total time spent in zones
The total time spent in zones shows you how much time all tags combined have spent in your different zones.
The percentages have to be taken with a grain of salt if you have overlapping zones: If a tag was 100% of the time in zone A, and at the same 100% of the time in zone B (because the zones are overlapping), the chart will show 50% for zone A, and 50% for zone B.
Time spent in zones
The time spent in zones shows for each tag how much distance it has travelled and how much time it has spent in each zone.
The same side note on overlapping zones for the Total time spent in zones widget applies here.