You may sometimes find that LiveStories mistakes ages (or other groupings) in your data for numbers that it wants to calculate the average or total for:
There's a simple way to fix this, and it's by adding some text to the age information.
For example, enter "60-69 years" instead of just "60-69".
Adding the text will prompt LiveStories to realize you want this information bucketed rather than added.
Give it a try and let us know how it works for you.