I have upgrade carpet padding in good shape. After I pull the carpet can I go over this padding? I am on a slab (never any moisture in the last six years) but would like the extra cushion under the floor.

No, you cannot use carpet padding under any floor other then carpet.
The underpadding sold with flooring is very thin. Carpet padding is to thick. The result would be the floor would crack at all the joints where they are put together.

Ken,

What you are looking for is underlayment not carpet pad. Check out a guide to laminate and engineered hardwood underlayment at a really informative flooring website. I suggest True Hardwoods