Zen Cart & Paypal Address

I have a zen cart shopping cart working.
However here are the problems:

1. when customers use paypal to make payment, zen cart always give free shipping if quantity discount module is used for the products.

2. zen cart does not grab paypal address correctly. It sometimes changes the nationality.

3. Need to put an edit button to change address (only occurs when non-express paypal is used).

Thats it!
Just need someone to make it more solid. Shouldn’t be too hard if you know your zen cart.