Difference in Page Views between Reports and Workspace

Hi,

I tried creating a freeform table in Workspace and the Key Metrics report under the Reports section in Adobe Analytics to calculate Page views using the same segments applied to both. However, the number of page views differs between the two sections. 

On looking further, I noticed that using some segment structures shows equal page views, while some don't.

Could you please help me understand why that would happen when the segments used in the two sections are exactly the same?