paypal pament doesn't add shipping

[ken1]

I am using the PayPal express checkout module that is in zen cart. I just noticed that if a customer makes a purchase and then uses the PayPal check out button, the shipping quote is not added in. The customer will only pay for the product and not the shipping.
I've looked and haven't found a setting to change that. When the user doesn't use the button he/she gets to choose the shipping, there is only one, then when they go to PayPal the charge is correct. Both product cost and shipping. Is there a way to fix that or should I be using one of the other PayPal modules.

[stevesh]

The shipping cost will be added when the customer returns from Paypal. Before that, Zencart has no way of knowing where the customer is, and can't calculate shipping.

[ken1]

Thanks for the clarification on how it works. I went all the way through the process and saw that it does add shipping at the end.
I did notice that the totals are different using the express button and not using it. The express button charge for shipping was $6.16 and not using it the charge was $7.25. Somewhere along the line I lost $1.09 in shipping. My only shipping is the new USPS module. Why does the shipping rate change when using the Express Pay button.