There is only a single address that can be passed for the PayPal transaction so whatever the user enters is the only one that they will see during the checkout. If you would like the user to be able to use their own address when they get to the PayPal site you should look for the following form element on the confirm page:
<input type="hidden" name="address_override" id="address_override" value="1" />
If you get rid of this element then the user should have the ability to use one of their own address or enter another when they get to PayPal.