It's been more than 72 hours since I purchased the GC and I've been trying to do the split transaction with my Amex Plat using Delta's desktop site to no avail. Everytime I click Complete Purchase it says "Oh no! We're sorry, but we are unable to process your request. Please try again later.
If this problem persists, please call Delta at 888-750-3284."
I'm guessing if I book over the phone it won't get posted as additional collection?