I'm also using the woo commerce gravity form extension and have been struggling to get the form to submit the information to the checkout. I have started a ticket with woo commerce, but they have not been able to help. Please let me know if you have any suggestions on how I can get this to work.
The main issue is that at the final step, to submit the quote, it takes the user back to step 1, when they first start the process. We need to have them go to the cart page that shows the option, and then to proceed to checkout, or to submit the quote.