Stats sales amount does not match when checking in different categories

[LauraCh]

1st question:

When I check my total sales in the category sales and orders I have an amount of let’s say 100 EUR.

When I check the category best categories and I add all the sales of the different categories, my total sales is different, let’s say 90 EUR.

When I check the category best customers and I add all the sales from the different customers, my total sales is different, let’s say 110 EUR.

When I check the category best selling products and I add all the sales from the different products, my total sales is different, let’s say 80 EUR. 

Why is that? Can someone explain me how to fix that?

 

2nd question: 

When I check the products in the category best selling products, my top product’s price is not accurate. It is more than twice the actual price I sell this product for (no matter the different prices per country or the different currencies)

How can I modify this number so that my stats and sales are accurate?

 

3rd question: 

I sell some of my products to France, where there is 20% VAT, is this VAT included in my sales?

Thank you so much.