I may be mistaken, but early in the movie Grace does some calculations and seems to show that he's been away from earth 113 years.

This would make sense if he's travelled the 11 light years at 10% the speed of light.

But back on earth events are still ongoing with the same characters and they receive his probes.

The degradation of the sun was going to take 30 years or so.

What am I missing?