Don't use time(). Use interval(). Time is a clock time, so is limited to 24 hours. Interval is a duration, so can be as long as necessary. Sandro's example uses "interval", though in this case as just a format on the number tab.
It appears that your chart is turning your times or intervals into dates. Hopefully setting it as an interval in either the data or on the number tab will fix that. I have no problem, for instance, if I convert Sandro's example to a bar chart.
As for taking away the SS data, just override the format. Like this, for intance:
interval(sum(MyInterval),'hh:mm')
Depending on what you're doing, that could also just be an override format on the number tab.
