Pivot table summary function, "Average" does not match worksheet function "Average"

Hi all... first time poster here. Hoping someone can show me the light.

I have a spreadsheet that contains survey scores and date of scores for individuals. I'm using a pivot table to display scores for individuals by month.

person Jan Feb Mar Apr GrandTotal
John 80% 70% 80% 75% 76.25%

The problem is that the Grand Total Average (calculated by the pivot table) does not return the actual average.

Anyone have any idea why?

Thanks Dav!

You helped me realize the pivot table is calculating the actual average and that my expectation was off base. I was indeed looking to validate by calculating an average of an average.