DP:


12/12: Made Dell Rewards Account, Ordered 2x100 Xbox GC &1x10 Xbox GC (Used promo code GAME10 as one order, could have maximized with 2 orders)
12/14: Chatted to ask about status, representative said order "prioritized". Later that day, all GCs downloadable through Dell Digital Locker
12/19: Statement credit for $10 GC showed on Business Platinum (charges posted separately)
12/20: Statement credits for 2 $100 GCs showed on Business Platinum

No problems ordering GCs with new account, thanks to this thread for useful information.