PayPal sends us quite a bit of data, and we do our best to make sure that data is both accurate and relevant. If you added PayPal after June 3, 2011 or added the PayPal permissions then your Sales information should be broken down in the following way:
Sales Tax (If applicable)
When we receive this data from PayPal, they send us the total of all three of these pieces. We check to make sure that they add up. In the rare case they do not add up, we display just the total, instead if showing you bad data. This means that in a few transactions you might see just a total of all three of these pieces, instead of the pieces broken down.
The work around right now if you want to see the pieces is to delete the total transaction, and add the sales, shipping income, and sales tax manually.