Vizlib Pivot Table - Formatted Export Settings - Text or Value
Under the Interactivity Tab of your Properties Panel, you can select one of two options for your export: Text or Values (a toggle button)
If you select Text - all of the values are exported as text. Calculation in Excel won’t be possible but you will keep the correct formatting.
If you select Values - all of the values are exported as numbers and the calculations will be performed as desired. (custom formatting might be altered)