Could be the same script with the added visuals in the vid. If your landing page copy is converting then that's a valid reason to mirror it in your vid. What some do and what I've done is break the sales letter into parts to create a set of say three videos. You can use video one on a squeeze page with a reverse optin - you let them watch part one first, then require an email addy to access part two. Then you deliver part two, then deliver part three/vid three with your call to action.